Trying to help a friend work the bug out of a new engine. New block (454), forged crank, new pistons, etc., new Dart rectangular port heads, Holly (800). Original Merc. ignition (454 Mag.). Idles fine, gets on plane fine up to about 4300 rpms, then it starts slowing down. Back off and wait about 30 seconds and it will go again. We checked fuel pressure and have about 4 lbs. when running. Is this enough????
Any ideas guys. My friend had this engine built thinking it would be very dependable. However, it just won't run. Any thoughs would help.