Let me start with I'm not much of a wrench - step by step shop manual guy at best. Anyway the holley carb 302/600cfm my car currently has been running rich from the day I bought it - tried to set idle/mixture and no luck. Check float level and gas was spewing from sight valve - set float as low as it would go to keep from flooding. Decided to buy a new 600 off ebay - not in original box but looked to be never mounted. The old carb hestitated when stepping on it and died especially after car warm up'd and ran for awhile - I thought it was related to carb running rich and flooding but mounted new carb and have the same problem. Step on it it hard it hesitates and dies. What should I look at next? Any help is appreciated - Thanks

 

I have the same basic setup a 66 with a 302 I put a new holly 600 on it when I put the motor in the car. It was a 2V motor before that with out any other mods to it. It also runs rich so much that the exhaust fumed will burn your eyes. It will hesitate when a jump on it but it does not stall. I think the 600 is too much carb for the present setup and a 400-500 may be better.

 

A 600 is a lot of carb for a stock 289. I second the downsizing. Get you an autolite 4100. If you motor was modified some it would be okay, but stock it's a bit much.