Born in ‘61
New Member
Does anyone know where I can find documentation, or know what the CFM rating of a 409 / 340hp Rochester 4 GC carb?
Rumor is it is a 750 cfm (?)
Rumor is it is a 750 cfm (?)
So they would be found on 390's,401's,and 389's or would it be later larger engines?And would it also be on olds 394's?Also does the high 600's mean closer to 700?I need to know if I want add these to my wrecking yard/swap meet list.The '409' 4GC's are great carbs!
Primary throttle bores are 1.562 and secondaries are 1.686. We used to experiment with different 4GC's back in the 70's and they were always quicker and faster than any AFB. They flow in the high 600's for CFM. Cadillac, Buick and Pontiac also used these big 4GC's.
It's all in the AMA specs at the GM Heritage Center.