Hi, I a have a 77 f150 4x4 shorty with a 429 and a 4 spd. The specs on the engine are as follows: 9.0 :1 compression, edelbrock performer intake, Summit cam (don't know what specs, but it doesn't lope), L & L headers, 2.5 inch Flowmaster exhaust, and stock DS ignition. My only future plan is to install a comp 268H cam in her. I have an older carter carb on it right now that is kinda tired, and I want to replace it with a new edelbrock. What size should I get? I use the truck for towing and roaring around scaring chevys! I had an edelbrock 600 on it for awhile, but it always seemed to run out of gas a high rpm. Any thoughts or experiences here?