I have a 1968 Cutlass with a 425 V8 that I got from a '67 Delta 88 and rebuilt back in 1996. After finding out a Holley 750 double pumper was too much carb, I ended up putting on a Holley 650 cfm with vacuum secondaries and larger jets. Now, 18 years later, the Holley is leaking all over the place and in need of a rebuild. Instead of rebuilding a 20 year old Holley, I'm tempted to switch to an Edelbrock.

I need some guidance - what size Edelbrock would be appropriate? I believe the engine compresses 10.5:1 (whatever the higher compression pistons for the 425 were). Mods include the following: Performer 455 aluminum intake, headers, later model Olds distributor with electronic ignition.

 

I would rebuild the 20 year old carb if the car runs well with it. Edelbrocks are ok but an electric choke version may not work with your stock air cleaner. Since the 650 Holley worked a would go with a 650 Edelbrock.

 

I would not switch to an edelbrock. I've had two of them and I still can't get it tuned perfectly. They are good carbs, but 1 size fits all is not the solution, not for someone who wants to tune it. I've been through 2 different 600cfm carbs, and the corresponding calibration kits, the 1406 and 1405 on a stock 72 cutlass and they still bog/hesitate. Rebuild the original Quadrajet, or the carb you have. If it ran good, no problems, I don't think it'd switch it.

If wasn't convinced maybe something else is causing my problems, It'd shell out the $175 to have the original quadrajet rebuilt by Hobb's in Pelham Nh.