Hot Rods 471 with (2) 2-barrel Carbs

This is an old HAMB post from 2013, but shows a 4x2 471 adapter. With your CAD skills and access to CNC machinery maybe you can copy one. I did one for a friend almost 20 years ago with only a manual Bridgeport and BAD (beer added design).
https://www.jalopyjournal.com/forum/threads/4-71-dual-quads.804755/

 

Thanks, Jim! I think that I could design it and have it CNC milled. I did find that exact type of adapter in your referenced post in the H.A.M.B. Classifieds and have PM’d him.

 

The above referenced item was sold. Ok, if I can’t find one I will build one. Now all I need is a firm decision on carburetors!.

 

I am thinking about running (3) Rochester 2G’s. I have read that 500 CFM rating is actually 435 CFM. Doing the math: 435/1.414 = 308x3 = 923 CFM total. That should be about right for my build. I can fab a carb adapter if necessary. Any other thoughts on running/tuning this combination would be greatly appreciated.

 

I would think you'll need to get built and see what needs tuned. From my experience, getting to idle is the biggest hurdle. I had to lap my butterflies to the bodies to keep them from sucking air with the blower pulling on them. Once that was handled it acted like it did N/A. I don't have any special carbs with the thicker blades.

Are you going to run it progressive or straight linkage?

 

I think putting 3 2cg's on a 4-71 will be a challenge. Also your math may say it needs that much cfm, but are you really going to run it at full throttle all the time? I think two 2300's will be plenty of performance!

 

This little Oldsmobile motor runs and winds like a small block Chevy on two carbs. Runs like a champ and has made some long hauls going to shows

 

if you want a big 2 bbl carb, try these guys. all the way to 1000cfm
http://www.candsspecialties.com/store/html/aerosolbillets1.html

 

Single Holley 750 CFM on my 1962 327(331 cu in) but it's all hidden under the hood.

 

Here's a 4 deuce set up on a local 3W. Note the early v-belt drive also. Very cool.

 

My buddy, Stu [R.I.P.] used to run a 327 with a 4-71 and two modern Holley 2 barrels on it. Said he liked it a lot better than the 2 Holley 4 barrels he ran on it first. I rode in the car [31 chevy 5 window] several times and it was smooth with no hesitations or jerks.

 

If you want to run a pair of Holley 500 (ish) 2 bbls on a 471 you run them back to back. makes them resemble a single 4. Holley made a 600 CFM annular discharge 2 bbl that was really popular with the short track crowd in the '70s and '80s. No reason to look the number up as it falls under good luck finding one. I have only seen one since returning to the US in '92.

I would probably consider running a single 4 or a pair. to get what I was after personally. Its about performance right?