Found this in my shed yesterday....
That's very cool stuff, Brooks. Thanks for sharing. I'm confused on one point though. What time frame are you saying this carburetor is from? I ask because the early factory style AFB carburetors were smaller than the 5 1/8" diameter where the air cleaner installs and that one appears to be 5 1/8" which indicates it is a later Competition style, like you do say. I bet it would be very responsive on a slant 6.
Yes you're right. I made an assumption that may not be correct.
......That were no Small throat AFB's that were 750 CFM.or above.i think that NHRA allowed the 400 CFM Comp Series as a replacement carb for stock. .if the stook one weren't
Available
For example, I have an Edelbrock 750 which is a NHRA legal replacement for a 65 Max wedge intake. Go figure that.
So ...again I'm guessing that the 400 CFM Competition Series was the correct replacement carb and CFM, and that the carbs were made by the same manufacturer definitely didn't hurt.
I'm saying that the secondary boosters pictured here are from A Competition series 750 CFM, stuffed inside the 400 CFM body,
That had the correct carb number to pass NHRA inspection.Even if the small throat AFB secondary boosters fit in the Competition series carb, I haven't seen a small throat AFB with a booster as big as the one pictured here
So if these were replacement carbs, then by using the 750 boosters he had more fuel flow , add that to the compression ratio increase I mentioned earlier, etc.etc
You get the idea