303 v8 rebuilt .030 over...AA carb rebuilt....points set, timing set...vacuum advance working... Starts and runs fine...pulls good up till about half throttle then looses power and falls on its face at full throttle. No black smoke out of exhaust... Suspect lean condition.... Any ideas on a solution?

 

Check your float level. Another area could be fuel pump, insufficient volume or rubber fuel line from tank could be collapsing shutting off fuel flow. When you reduce power does the engine immediately smooth out?

 

I set the float per the Rochester repair manual... Yes , if you let off it runs fine... It Had a fuel pump issue and I rebuilt it with new diaphragms....I do have a small electric pump i may put in line with it to support it... That may increase the volume, if that's the issue. All the rubber fuel lines are new.

 

Check your vacuum advance.If it hasn't been rebuilt lately the diaphragm may have deteriorated to the point you are not getting any advance..... Tedd

 

Another overlooked area is the fuel bowl. I think your car has an in line fuel bowl filter? I have seen where the bowl had contamination that was sucked up into the filter under high fuel flow effectively starving the engine causing power loss. Fuel tank; have you checked it for debris. There should be a fuel pickup filter there. Another question; how did the engine perform prior to carburetor repair?