Have a "69" Malibu with a 350 bored .030 over, a mild cam, performer rpm intake, and a 750 cfm Edelbrock carb. Was looking at something else last night on the forum and came upon a post where a guy claims that a 600-650 cfm carb is more desirable for the street. He claimed that the smalller carb will yield better performance especially at low and mid range and will improve fuel economy. He's got me to wondering if I would be ahead to swap out my 750 for a smaller carb or maybe just to rejet the primary's smaller ( as far as I know they are the orginial primary jets ). I drive this car only on the street and to car shows,cruise-in's, ect, so the racing point of view is not a factor. The car in low always seemed a little docile until it got the r's up a little bit. I have always blamed that fact on the cam , but now it's got me to wondering. What do you guys think, is this guy for real or just full of it ?


Ted

Can you barrow a carb to try? I would bet your engine (and you) will like a 600 better, as it is built and the way you use the car.

yes the 600 would be a better carb for your engine, rejetting wont fix the problem with your 750 as it will make it run lean. the CFM is the amount of air allowed to be pulled throught the venturies not the amount of fuel, the amount of fuel is dictated by the vacuum and leaning out the fuel will just do that lean out the fuel, not lessen the air at the same time.

Yep, agree with the others. I bet you'll be very surprised at the difference. Stick with a vacuum secondary for the street...I say this in case you're thinking of changing over to a Holley. But the Edelbrocks are a good carb.