I had an Edlebrock 600cfm but the engine shop suggested I upgrade to the 750cfm based on the rebuild they did for me. I've heard Holley is a better carb for performance so my question is which Holley 770 should I get for my 350 Rocket. I have the Edlebrock 7111 performer intake...

 

unless it has a lot of compression and a big cam the 750 is probably too big for it. what are the specs on the engine? on a basically stock rebuild the edelbrock 600 you have should be fine.

 

The compression is 9.5:1, bored over .30, Voodoo 262 Cam, and the intake mentioned above the Edlebrock 7111.

 

I would use a vacume secondary 750 with an electric choke. My engines always liked a bigger carb, never liked the 2 600s I had.

 

I agree, IMO Olds engines "like" bigger carbs. I have a 770 Street Avenger on my 10 to 1 355 and it runs great. I had a 670 on a milder 355 and went up several jet sizes to get it to run the best.

 

Define "performance". The Holley is a better quarter mile carb. If you primarily intend to drive on the street, I'd consider something else.