HI, wolffclub, You said the engine was rebuilt, did you stuff rags into the exhaust and intake ports, if so did you remove ALL THE RAGS. One way to check is to get the truck idling and feel the exhaust pulses at the tail pipes. Also check the temperatures of the pulses, they should be the same, if not you have a blockage in the exhaust or intake. PS, My dollar is one the way. Have Fun, Brian
