Ok long time listener first time caller, Im 22 and this is the first engine I have built. I may not have all the puzzle pieces yet to help you guys decode this problem, but hopefully I can narrow down the cause of the source of the problem. I have a 387: 2 piece 4 bolt main block, Malhe .040" over forged +5cc pistons that are supposed to give 11:1cr with 64cc heads, Forged Eagle 5.7" rods, Eagle cast Steel crank (3.75"). cant remember what i filed the rings to, I know one was .018". (Went off what a 70-71 hi po corvette 350 had in a old chiltons book. Pistons are .014-15 in the hole. Cam is comp cam .460/.460 lift, 110deg lobe separation with 218/218 dur at .050. Cam was previously in engine and properly broke in and has only 5000 miles on it. Heads are 76cc World Stock Replacements that were previously on engine. gaskets are .040" The valves leaked, but I lapped the valves and they did not leak before I put them back on. Carb is a carter 750 currently and manifold is a edlebrock performer intank . Distributor is a Pertronix flame thrower. Rotating assembly were all professionally balanced and sized for factory errors, cylinder walls were honed. I have yet to drive the car (still on blocks), Engine starts up and idles. Dad says it runs bad, Lazy throttle response, and blows fuel back out of the carb under load. Did a compression test with a old snap on set and Its design only allowed me to access 3 cylinders. and They were all over; 225, 170, 115. My dad thinks maybe we put the cam in a the Advance or retarded position. I dont know, maybe you guys might have an idea?