Best carbs for a 3x2 on a 327?

I want to run a 3x2 setup on my relatively hot 327 that's going in a Model-A. Trying to decide which carbs to run on it. I'm wanting to make relatively high cfm as this motor is pretty heavily built.

What kind of numbers can you get out of 94's & 2G's?

 

I'd run 2g's. Well actually I do. They're cheap, easy to get ahold of and, when run progressive, easy to tune.

 

If you want performance then a Barry Grant six shooter with 3- 250 CFM Demon carbs would give you what you need.

 

I'd opt for the Rochester 2GC carbs.

You can run 3 of the small-base carbs and end up with about 600 CFM ('57 347 & '58 370 Pontiac Tri-Powers used this setup).

Or run one small base in the center and 2 of the large base carbs for the end carbs and end up with about 750 CFM ('59 -'65 389 & '63 -'65 421 Pontiac Tri-Power).

Run all 3 large-base carbs for around 800 CFM total (the '66 389 GTO & 421 Tri-Power big Pontiacs came this way).

I'm using Pontiac factory setups for reference here since I'm familiar with them.

Three of the 94s will only net you about 450-500 CFM total.

 

Any one know what the cfm,s on 97's...I'm running 4 of em

 

Thanks much man. That's helpful. According to the builder I want to be in the 650-700 range for this particular engine.

 

Old original 97's run 150 cfm's. The New English 97's flow 162 cfm's.

 

Thanks uncle max...

 

my information says that the 2G's are 280 CFM, x3 is 840 CFM

 

Small or large base?

I've seen the '66 Pontiac Tri-powers (3 large-base carbs) listed by different knowledgeable sources at anywhere between 780 and 888 cfm for this unit.

Either way, the 2G Rochesters should be the best way to get 700+ CFM.

 

thats a small base 2G @ 280 CFM. 840 is a lot of CFM on 327 cubes, but works OK. some times its hard not to open them up between all 4 gears!

 

I agree with not going with 97s or Holley 94s.

I'd go the Stromberg WW/Carter BBD/Rochester 2G route - especially the latter, due to availability of off-the-shelf 3x2 setup goodies.

~Jason

 

I'm going stromberg 48's on my 283

No reason (exept mabey space) you couldnt go newer style holley 2 bbls either

 

2 bbl carbs flow rate are at 3.0 in Hg not 1.5 in Hg like 4 bbl carbs are rated so the comparison is wrong.

4BBL Flow = 2BBL Flow / 1.414.

For example: A 500 CFM 2BBL Carb actually flows 353.606 CFM on the 4BBL scale


Roger

 

Gleeser,i run the 2G's with the progressive from speedway works just fine.