Awesome! Another Datsun nut!
This is a current post, mostly lots of planning at this point, but progress is happening!
Luke.
LTJ's 1981 DATSUN STANZA (A10) WANNABE RALLY CAR. SOLD and moving.
- Thread starter LukeTheJoker
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This is a current post, mostly lots of planning at this point, but progress is happening!
Luke.
right on bro.
these lil datsuns are sweet cars.
good luck with it.
sean
these lil datsuns are sweet cars.
good luck with it.
sean
Not much to show yet, but things are moving along, I will hopefully have this on the road before the big build-off starts May 1st, I will run it standard until the build-off is over so I don't get too distracted...
In the meantime been doing heaps of research on engines, gearboxes, diffs, brakes, seats, bodywork...etc...
Looks like I have fluked a good combination with the particular car I got and the spare engine I have in the backyard...
The spare engine as I have mentioned before is the taller deck, low compression L20b 2 litre from a 910 Bluebird, they are a good swap due to the direct bolt in and bigger capacity, also it brings with it the 5 speed box...
If you want to build it for a bit more power you need to get some more compression in it, usually this is done by either doing a full rebuild and swapping to flat top pistons or finding one of the increasingly rare 'supposedly' Japanese market only SSS "Peanut" closed chamber heads...
Here is a comparison of a closed chamber peanut and a open chamber standard L20b head (pics thanks to Google):
You can see why it results in higher compression...
I have been doing much research on finding a high compression head as the motor is still in good condition and not needing the expense of a rebuild just yet, they are available, but hard to find and expensive, in fact some people are welding on their stock heads to close the chambers up. so, hard to find, unless you happen to fluke one on a complete motor from someone who does not know what they have...
Or, due to Nissan/Datsun using up whatever left overs are around when building the last cars of a particular model, you may find your 'last of the run' Stanza already has a high compression closed chamber head, which just so happens to be what I did! The current motor has the W53 head, which according to http://www.olddatsuns.com/html/tech/head_ID_2.htm will most likely be a "peanut" high comp head!
The other thing I wanted was a bit hotter cam, nothing too ridiculous, just enough for a lumpy idle and a bit more top end, started doing some research on what cam to get, and what rev range to aim for and decided on one designed for 3000-6500rpm, which would be plenty for a nice street-able car, checked out the recommended lifts and durations to accomplish that and went looking, turns out the cam used on the 1600 SSS uses the same specs, so that made it easier to find, so I could now search for that particular cam, turns out that item number is the same as the standard cam on 910 Bluebirds??? What???
How does that work? I ran the 910 motor before I pulled it and it was not lumpy at all... So that can't be right...
More Google-jitsu and head scratching and I happened upon the answer, yes they are the same cam, but due to the low compression of the L20b motor, it actually behaves very mild...
More questions asked, more answers found, and I am thinking well maybe that cam is not big enough then for a L20b? So I searched some Australian rallying sites and they all say use that cam, with a peanut head, and it gets a lumpy idle and the optimal revs is 3500-7500!
I guess that will do then!
So, when the time comes, I will pull the head off the L16 to confirm it is a high compression "peanut" and then drop it onto the L20b but switch in the L20b cam, a bit of match porting to the larger runners of the 2 litre intake and I should have a decent little engine!
A 32/36 Weber will more than likely get the job on top of the intake. I also have a twin Hitachi (SU copies) set up off a 180b SSS, but I have been reading that they are more trouble than they are worth. I would love a pair of sidedraft Webers, but that would just be asking for trouble if I ever get pulled over and the car inspected for legalities, at least the 32/36 Weber can be hidden under the factory air cleaner with some creative welding...
Next step was exhaust, the exhaust itself I figure I can manage ok with my tools, but I figured I would look at some headers/extractors in front of it to increase flow out of the motor. Went looking for suggestions on the Datsun forums and found that apparently the stock L16 cast exhaust manifold flows better than almost all headers and are tuned length, so armed with photos from the forum, I went looking at my motors to confirm if I had that manifold, turns out I do, in fact both motors have that exact manifold!
I was looking at a lightened flywheel as well but the forums also suggest this would be a mistake, as they are already fairly light and lightening them more makes it hard to match engine revs to gear speeds when shifting, it also makes they incredibly easy to stall with a hot cam apparently...
So, looks like I will be saving quite a bit of my intended budget from the motor build...
With that set-up it should result in around 140hp at the flywheel, which may not sound like much, but remember this car only weighs 900kg (>2000lbs) so it should be plenty to have some fun with! It is also probably approaching the limit of what the 910 gearbox can handle, and I don't what to shell out for a Z box...
I managed to find a local diff expert and asked him what diff and centre he would run out of the options I have, and he said that the RN20 Hilux with a late model LSD centre would be by far the best option, when I mentioned the possibility of changing to a Torsen centre he said don't bother, he can shim the standard LSD up as far as I want and in such a light car even the untouched LSD would be more than enough...
He also mentioned that if I ever decide to do a swap to a turbo Sr20 or something else, the Hilux diff should be good for 400+ hp in such a light car... Good to know I guess, but not planning on doing that...
I will probably stump up the money for the pre-made Mazda RX-7 front disc brake and 5 stud conversion, as it comes with an engineering certificate and so will make all the mods easier to get certified, the rear will probably be R31 Nissan Skyline callipers over EL Ford Falcon rear discs, there is no pre-certified option with the Hilux diff, but by using those particular parts the engineer will have a known basis for certifying them as they are a common conversion.
Only thing I have not sorted yet is re-setting the rear coil springs, they sit on top of the diff and the Hilux has bigger axle tubes, so it will raise the rear of the car. There are a few local shops who do spring re-setting and even the manufacturer who made the current lowered springs that are in the car can make custom lengths for reasonable prices. Cutting coils is not legal here, so I won't be doing that.
Think I will be going with 15" steel wheels from a Falcon too, then I can get the offsets changed cheaply to whatever will be needed to suit the car with all it's miss-matched pieces.
I happen to have a set of them here too, so that makes the decision that much easier!
Test pic:
Sorry for the long update, I know it is far more information than most will care about, but for those members who do want to know, the more detail, the better!
Luke.
In the meantime been doing heaps of research on engines, gearboxes, diffs, brakes, seats, bodywork...etc...
Looks like I have fluked a good combination with the particular car I got and the spare engine I have in the backyard...
The spare engine as I have mentioned before is the taller deck, low compression L20b 2 litre from a 910 Bluebird, they are a good swap due to the direct bolt in and bigger capacity, also it brings with it the 5 speed box...
If you want to build it for a bit more power you need to get some more compression in it, usually this is done by either doing a full rebuild and swapping to flat top pistons or finding one of the increasingly rare 'supposedly' Japanese market only SSS "Peanut" closed chamber heads...
Here is a comparison of a closed chamber peanut and a open chamber standard L20b head (pics thanks to Google):
You can see why it results in higher compression...
I have been doing much research on finding a high compression head as the motor is still in good condition and not needing the expense of a rebuild just yet, they are available, but hard to find and expensive, in fact some people are welding on their stock heads to close the chambers up. so, hard to find, unless you happen to fluke one on a complete motor from someone who does not know what they have...
Or, due to Nissan/Datsun using up whatever left overs are around when building the last cars of a particular model, you may find your 'last of the run' Stanza already has a high compression closed chamber head, which just so happens to be what I did! The current motor has the W53 head, which according to http://www.olddatsuns.com/html/tech/head_ID_2.htm will most likely be a "peanut" high comp head!
The other thing I wanted was a bit hotter cam, nothing too ridiculous, just enough for a lumpy idle and a bit more top end, started doing some research on what cam to get, and what rev range to aim for and decided on one designed for 3000-6500rpm, which would be plenty for a nice street-able car, checked out the recommended lifts and durations to accomplish that and went looking, turns out the cam used on the 1600 SSS uses the same specs, so that made it easier to find, so I could now search for that particular cam, turns out that item number is the same as the standard cam on 910 Bluebirds??? What???
How does that work? I ran the 910 motor before I pulled it and it was not lumpy at all... So that can't be right...
More Google-jitsu and head scratching and I happened upon the answer, yes they are the same cam, but due to the low compression of the L20b motor, it actually behaves very mild...
More questions asked, more answers found, and I am thinking well maybe that cam is not big enough then for a L20b? So I searched some Australian rallying sites and they all say use that cam, with a peanut head, and it gets a lumpy idle and the optimal revs is 3500-7500!
I guess that will do then!So, when the time comes, I will pull the head off the L16 to confirm it is a high compression "peanut" and then drop it onto the L20b but switch in the L20b cam, a bit of match porting to the larger runners of the 2 litre intake and I should have a decent little engine!
A 32/36 Weber will more than likely get the job on top of the intake. I also have a twin Hitachi (SU copies) set up off a 180b SSS, but I have been reading that they are more trouble than they are worth. I would love a pair of sidedraft Webers, but that would just be asking for trouble if I ever get pulled over and the car inspected for legalities, at least the 32/36 Weber can be hidden under the factory air cleaner with some creative welding...
Next step was exhaust, the exhaust itself I figure I can manage ok with my tools, but I figured I would look at some headers/extractors in front of it to increase flow out of the motor. Went looking for suggestions on the Datsun forums and found that apparently the stock L16 cast exhaust manifold flows better than almost all headers and are tuned length, so armed with photos from the forum, I went looking at my motors to confirm if I had that manifold, turns out I do, in fact both motors have that exact manifold!
I was looking at a lightened flywheel as well but the forums also suggest this would be a mistake, as they are already fairly light and lightening them more makes it hard to match engine revs to gear speeds when shifting, it also makes they incredibly easy to stall with a hot cam apparently...
So, looks like I will be saving quite a bit of my intended budget from the motor build...
With that set-up it should result in around 140hp at the flywheel, which may not sound like much, but remember this car only weighs 900kg (>2000lbs) so it should be plenty to have some fun with! It is also probably approaching the limit of what the 910 gearbox can handle, and I don't what to shell out for a Z box...
I managed to find a local diff expert and asked him what diff and centre he would run out of the options I have, and he said that the RN20 Hilux with a late model LSD centre would be by far the best option, when I mentioned the possibility of changing to a Torsen centre he said don't bother, he can shim the standard LSD up as far as I want and in such a light car even the untouched LSD would be more than enough...
He also mentioned that if I ever decide to do a swap to a turbo Sr20 or something else, the Hilux diff should be good for 400+ hp in such a light car... Good to know I guess, but not planning on doing that...
I will probably stump up the money for the pre-made Mazda RX-7 front disc brake and 5 stud conversion, as it comes with an engineering certificate and so will make all the mods easier to get certified, the rear will probably be R31 Nissan Skyline callipers over EL Ford Falcon rear discs, there is no pre-certified option with the Hilux diff, but by using those particular parts the engineer will have a known basis for certifying them as they are a common conversion.
Only thing I have not sorted yet is re-setting the rear coil springs, they sit on top of the diff and the Hilux has bigger axle tubes, so it will raise the rear of the car. There are a few local shops who do spring re-setting and even the manufacturer who made the current lowered springs that are in the car can make custom lengths for reasonable prices. Cutting coils is not legal here, so I won't be doing that.
Think I will be going with 15" steel wheels from a Falcon too, then I can get the offsets changed cheaply to whatever will be needed to suit the car with all it's miss-matched pieces.
I happen to have a set of them here too, so that makes the decision that much easier!
Test pic:
Sorry for the long update, I know it is far more information than most will care about, but for those members who do want to know, the more detail, the better!
Luke.
Nissan did do some weird stuff in mid 80's. This is for the 6cyl L engines, but Here's a N47 head in the middle and another N47 on the right..... The middle is from a L28 and the Right is from a L24E (maxima).... Same head casting number, Completely different chamber shape and CR...
Regardless, I'm loving my High CR L28 mild / street Cam really helps btw.
Regardless, I'm loving my High CR L28
mild / street Cam really helps btw.
From what I have found the W53 should be the equivalent of the right hand one with the full closed chamber.
Been doing more research on cams, and I may end up going a bit more extreme than the factory 1600 SSS/L20b cam, but I can make that decision later.
Also need to get a heavier duty clutch and pressure plate, apparently the standard are fine with a worked L20b, but once you add an LSD and fatter tires you can run into issues, may as well do it while it is out of the car to save work later on!
In the meantime been doing more research on carbs and found that the Weber 32/36 would be limiting on my proposed set up and was told to consider the big brother 38/38 DGAS Outlaw.
It looks the same on the outside but instead of a 32mm primary and a 36mm secondary it run synchronous 38mm throats...
Apparently the 2 barrel 350 Holley is also twin synchronous 38mm throats but can suffer with low vacuum signal strength to the venturi boosters on a small capacity motor, fine at full revs, but flat spots in the mid range, a company here in Australia modifys them to fix the issue by fitting annular boosters, this drops the cfm to 330 but improves fuel flow and signal at lower vacuum levels so I might look into that.
Either carb I think I can modify the air cleaner to fit to keep it as stock looking and stealth as possible under the bonnet.
Should have this thing passed inspection and on the road soon!
Luke.
Just got off the phone with ReCarb Australia after talking with them regarding carburettor choices, they said the 32/36 is definitely too small, the 38/38 DGAS outlaw will limit my top end too as it actually runs the same size bores as the 32/36 just with bigger synchronous throttle blades, the modified 330 Holley would work, but may need a significant amount of fiddling with jets and possibly even soldering up passages and re-drilling them smaller in the idle circuit...
Then he mentioned the Weber IDF carbs, which would work perfectly, as they are completely modifiable, unfortunately they are a very tall carb, and use a minimum 2 inch velocity stack on top as well, so hiding it under my stock air cleaner for a stealthy engine bay would be an issue.
BUT! He did mention the Weber ADR which is another carb they re-configure themselves to suit applications, it starts out as a twin throat ADF carb usually used on racing Fiat Millafioris, then they modify it, so that seems like a good possibility, just waiting now on an email from him with specs and pics as they don't list it on the website...
Luke.
Then he mentioned the Weber IDF carbs, which would work perfectly, as they are completely modifiable, unfortunately they are a very tall carb, and use a minimum 2 inch velocity stack on top as well, so hiding it under my stock air cleaner for a stealthy engine bay would be an issue.
BUT! He did mention the Weber ADR which is another carb they re-configure themselves to suit applications, it starts out as a twin throat ADF carb usually used on racing Fiat Millafioris, then they modify it, so that seems like a good possibility, just waiting now on an email from him with specs and pics as they don't list it on the website...
Luke.
Just curious, but maybe factory just milled the head castings for some applications? Maybe some were defective and head gasket surface did not "clean up" so they just milled 'em down more?
Nah, I've measured the thickness before and they're identical. otherwise, you'd be skipping teeth all day on the cam sprocket without shims.
I guess they figured since it's on a different model of engine, people won't even bother swapping it... so lets just use the same casting number lol.
beefier cam than the factory grinds deffenetly helps with higher CR engines.... I have 275/275 right now and it's real streetable. no lumpy cam idle (although I like those too).
Why not DCOES or some side drafts? I'm sure there's plenty of used ones in australia... just rebuild em and slap it on.
I should clarify after years in a machine shop. They use a common casting # . Machine the horizontal surfaces first operation, then they bore for the cam.
Good info on the cam!
Dcoe's and sidedrafts would be cool, but frowned upon by the local Police, even though on any car before 1986 it is legal to change carbs provided it runs a pcv valve, apparently they take a dim view of modified engines and send you off for testing anyway... With a downdraft I will be able to remake the base plate of the original air cleaner to suit the new carb and hide it all underneath, this is also the same reason I am not considering a Weber IDF, as I would have to raise the air cleaner 3 inches to clear the velocity stacks...
Not so sure on the modified Weber ADF carb that the guy mentioned to me today, it seems they only have twin 34mm throats and are typically used on 1300-1600cc Fiats, so would be too small unless they are boring the throats out significantly?
Getting sick of it all to be honest, wonder if I can build a stealthy manifold and hide two 32/36 progressive Webers under the original air cleaner???
Will probably end up with the modified 330 Holley or a Holley 250 which I didn't know existed till today, I ran a 500cfm 2 barrel Holley on both a 250ci (4.1 litre) Ford Cortina six and a 3F powered 4 litre LandCruiser in the past, both low revving pushrod motors that probably topped out at 5,000 rpm, admittedly the carbs were too big, but the were both drivable just fine, surely a high revving 2 litre can handle the same ratio?
The way I figure it is this:
4 litres revved to 5,000rpm and then divided by 500cfm is 40,
4.1 litres revved to 5,000rpm and then devided 500cfm is 41,
2 litres revved to 7,000rpm and then divided by 330cfm is 42.4,
2 litres revved to 7,000rpm and then divided by 250cfm is 56
Both those numbers are a better ratio than the Landcruiser or Cortina ran...
Apparently the lighter the car and the lower the gearing the more forgiving an over-carbed situation is, so I might just get away with it...
Apparently Offenhauser used to make a 4 barrel dual plane manifold for these motors, there are quiet a few people running a 390cfm Holley on them...
Luke.
Luke,
Interesting ebay redline DGEV weber carb here w/info.
http://www.ebay.com/itm/Weber-Redli...980-/301458683923?hash=item4630567813&vxp=mtr
Manifold:
http://www.ebay.com/itm/Datsun-510-...mog-/151646258865?hash=item234ed246b1&vxp=mtr
I know its USA ebay and freight would be a killer but maybe good to study anyways.
Interesting ebay redline DGEV weber carb here w/info.
http://www.ebay.com/itm/Weber-Redli...980-/301458683923?hash=item4630567813&vxp=mtr
Manifold:
http://www.ebay.com/itm/Datsun-510-...mog-/151646258865?hash=item234ed246b1&vxp=mtr
I know its USA ebay and freight would be a killer but maybe good to study anyways.
Thanks for the link Horsefarmer! That is actually cheaper than here even with the expensive freight!Luke,
Interesting ebay redline DGEV weber carb here w/info.
http://www.ebay.com/itm/Weber-Redli...980-/301458683923?hash=item4630567813&vxp=mtr
Manifold:
http://www.ebay.com/itm/Datsun-510-...mog-/151646258865?hash=item234ed246b1&vxp=mtr
I know its USA ebay and freight would be a killer but maybe good to study anyways.
That carb is actually the 32/36 I was referring to, interesting it says up to 2.6 litres, that is the first time I have seen that written.
I was told that it probably would be limiting above 6,000rpm, but it might be worth me re-visiting my research on it.
I have converted a 910 Bluebird with an L20b to the 32/36 DGV for a friend and it went really well, but that was a stock motor, not sure if it had the capacity left for the gains I want...
Been reading up on L20b's with 350 Holleys, it seems it has been done before by a few people with good results, but there are plenty of people who have not tried it that say it will be far too much carb for the motor, there is even some videos on Youtube with them running, admittedly mostly on dirt circuit or full race cars, even some with 500cfm Holleys, but there are some road cars with 350's too, and they sure sound good!
Really not sure what I am thinking at the moment, my research shows that if I had a 100% efficient motor I would need 290cfm, but that is measured at the 1.5" of vacuum that is used for 4 barrel carbs, 2 barrel carbs are rated at 3" of vacuum, to convert a 2 barrel rating to a 4 barrel rating you divide it by 1.414, so a 350cfm 2 barrel actually comes out at 247cfm...
But, my motor will not be 100% volumetric efficient, probably only 85-90% which most calculators put at 250cfm, seems like it would be almost perfect with a 350?
I might end up splitting the difference and getting the modified 330 Holley with the annular boosters, it costs $100 more than a standard 350 Holley or the Weber 32/36 DGV and the same as a Weber 38/38 DGAS but it would be almost guaranteed to be pretty close to perfect... In theory anyway.
Luke.
Seems like the issue is "bog" I guess that's the term for opening up to much carb flow too fast? I know some secondaries are mechanical but some are vacuum operated. Think the vacuum type opens more gradual. Also the listing mentions "The DGEV also has a power valve circuit to facilitate low vacuum running conditions." Maybe less bog?
Had one BITD on a German 2 liter 4 cyl in a Ford Pinto
with a 5 speed.
Car was pretty bad but that was a wonderful running motor and never a bit of trouble with the carb. I remember the secondary on that 1 was vacuum.
Had one BITD on a German 2 liter 4 cyl in a Ford Pinto
with a 5 speed.Car was pretty bad but that was a wonderful running motor and never a bit of trouble with the carb. I remember the secondary on that 1 was vacuum.
Info about secondary actuation - maybe it will help.
http://www.hotrod.com/how-to/engine/1306-vacuum-or-mechanical-secondary-carburetor/
"
Controlled-secondary carbs may offer more flexibility in a setup where airflow velocity through the boosters is insufficient for good throttle response. Because it feeds the engine only as much air and fuel as it will accept at different rpm and load ranges, a controlled-secondary carb has the ability—within reason—to self-adjust to engine size and offer more tuning flexibility on mild engine and drivetrain combos. This type of carb can provide a broader operating range than would normally be practical for a given-size carburetor.
Properly tuned, controlled secondaries should deliver superior fuel economy compared with a mechanical-secondary configuration—which is one reason most OE-application Holley carbs back in the muscle-car days had vacuum secondaries. Their broad adaptability for a wide range of engine sizes also means Holley doesn't need to offer a large variety of vacuum-secondary carbs with different cfm ratings. For example, if you use a 750-cfm vacuum-secondary carb on an engine that only needs 650 cfm, the vacuum secondaries probably won't open fully (even with the softest diaphragm spring), so it's pretty hard to over-carburete a controlled-secondary configuration."
http://www.hotrod.com/how-to/engine/1306-vacuum-or-mechanical-secondary-carburetor/
"
Controlled-secondary carbs may offer more flexibility in a setup where airflow velocity through the boosters is insufficient for good throttle response. Because it feeds the engine only as much air and fuel as it will accept at different rpm and load ranges, a controlled-secondary carb has the ability—within reason—to self-adjust to engine size and offer more tuning flexibility on mild engine and drivetrain combos. This type of carb can provide a broader operating range than would normally be practical for a given-size carburetor.
Properly tuned, controlled secondaries should deliver superior fuel economy compared with a mechanical-secondary configuration—which is one reason most OE-application Holley carbs back in the muscle-car days had vacuum secondaries. Their broad adaptability for a wide range of engine sizes also means Holley doesn't need to offer a large variety of vacuum-secondary carbs with different cfm ratings. For example, if you use a 750-cfm vacuum-secondary carb on an engine that only needs 650 cfm, the vacuum secondaries probably won't open fully (even with the softest diaphragm spring), so it's pretty hard to over-carburete a controlled-secondary configuration."
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Yeah, it is the possibility of "bog" that worries me...
It seems hard to find a vac secondary carb smaller than the Holley 390, but it may explain why a few people run the 4 barrel 390 instead of the 2 barrel 350 even though it is significantly larger again. (390 compared to 247cfm)
Did some more in depth research on the Weber ADF carb suggested by the helpful carburettor guy, I found on their website they make kits to fit them to many cars, starting with 2.4 litre cars and all the way up to 3.3 after which they switch to the modified 330 Holley which they suggest until well into the 4 litre bracket...
I figured, well maybe he does know what he is talking about, so I went searching on Google once again for more info, turns out that yes, they were used on Fiat 124's and the like but that was usually the 32ADF, and even then it was a performance option from the factory, ok, maybe not quite so bad as I thought, then I found out that there is a bigger model, the 34ADF, pretty sure this is the one he was talking about.
Sounds promising as although the throttle blades only measure 2x34mm compared with the 32 and 36mm blades of the DGV which I believe may be just a bit too small, it is the venturis themselves that are interesting, the ADF venturis both measure 29mm, compared with 26 and 27mm on the DGV.
After learning that I went searching for cfm specs on the ADF carb, turns out they run 320cfm in standard form, that is of course 2 barrel rating so 226cfm in 4 barrel terms, they can also be skimmed out 60 thou at the choke point which increases the cfm to 354 (250cfm 4 barrel rating). Even in standard form the 34ADM is good for around 160hp, about 20hp more than my set up should make.
The big advantage with the ADM over the Holley would be the progressive nature with one throat staying closed until half throttle, as opposed to the synchronous throats on the Holley, less chance of bog and probably save a bit of fuel when just cruising along...
Might be worth another call to the carby guy when the time comes, don't want to bother him too much before then.
Luke.
It seems hard to find a vac secondary carb smaller than the Holley 390, but it may explain why a few people run the 4 barrel 390 instead of the 2 barrel 350 even though it is significantly larger again. (390 compared to 247cfm)
Did some more in depth research on the Weber ADF carb suggested by the helpful carburettor guy, I found on their website they make kits to fit them to many cars, starting with 2.4 litre cars and all the way up to 3.3 after which they switch to the modified 330 Holley which they suggest until well into the 4 litre bracket...
I figured, well maybe he does know what he is talking about, so I went searching on Google once again for more info, turns out that yes, they were used on Fiat 124's and the like but that was usually the 32ADF, and even then it was a performance option from the factory, ok, maybe not quite so bad as I thought, then I found out that there is a bigger model, the 34ADF, pretty sure this is the one he was talking about.
Sounds promising as although the throttle blades only measure 2x34mm compared with the 32 and 36mm blades of the DGV which I believe may be just a bit too small, it is the venturis themselves that are interesting, the ADF venturis both measure 29mm, compared with 26 and 27mm on the DGV.
After learning that I went searching for cfm specs on the ADF carb, turns out they run 320cfm in standard form, that is of course 2 barrel rating so 226cfm in 4 barrel terms, they can also be skimmed out 60 thou at the choke point which increases the cfm to 354 (250cfm 4 barrel rating). Even in standard form the 34ADM is good for around 160hp, about 20hp more than my set up should make.
The big advantage with the ADM over the Holley would be the progressive nature with one throat staying closed until half throttle, as opposed to the synchronous throats on the Holley, less chance of bog and probably save a bit of fuel when just cruising along...
Might be worth another call to the carby guy when the time comes, don't want to bother him too much before then.
Luke.
JaxRhapsody
Rhapsodic Laviathan
You could also always have whichever carb rejetted. You could get a 390, and if it's too much, have it downjetted some.
