Carb CFM recommendations

thecatsfan said

The reason I like the square bore carb is the larger primaries - and you are right, that's all this car will use 99% of the time. Edelbrock provides the adapter plate with the carb for a direct bolt on since they don't offer a square bore intake for this engine. But I can see your point. Thanks!

Click to expand...

Welllllll...........
The big advantage of a 4 bbl over a 2 bbl is that the primary barrels will not cause a restriction at high rpm.
Soooo
Smaller primaries should not be of concern because when more air is needed, the secondaries will open and insure no restriction of concern.

The advantages of smaller primaries is the potential for better effeciency and throttle response.
With bigger primaries, the throttles need to open less to get the same rpm.
This means the engine is getting fuel is mixed in from the 'idle circuits' at higher rpms compared to an exactly the same carb with smaller primaries.

In reality they all work reasonably well.
My only point was that the small primaries are not a disadvantage.

Sticking with a same 'pattern' means less chance of issues, and better chance the cylinder to cylinder fuel distribution will be better.