Hi there. I am looking for some carb advice, I have a 67 cutlass with an early 70's olds 350. The guy I bough the car from put a Holley 750 double pumper elect choke with vacuum secondaries. I was told both motor and carb have been rebuilt recently. I have been told this carb is too big for my motor. It does not accelerate very good. I am looking for a new carb without spending a lot of $$ to replace. I have been advised to go with Holley 670 or 570 street avenger. Any suggestions is appreciated

 

Welcome to the site, post some pictures of your car when you get a chance. You can't have a double pumper vacuum secondary carb. It's either one or the other, Ill assume a vacuum secondary. While a 750 may be a bit larger than what you need it should not be a dog. Is your engine stock, what intake, does it have points or HEI or??? What transmission, rear end gearing and tire size?

 

If you have a vacuum secondary Holley, then you may need to tune the secondary diaphragm for optimal operation (as well as the primary jetting and accelerator pump). I once had a Holley 600 vacuum secondary carb and I had to play around with the secondary springs in order to get it to launch as well as the QJet that was previously on the engine. There was a significant difference in acceleration before and after tuning the secondary opening rate.