I resently had a motor built, for a 1990 GMC 4x4, the old motor (5.7) died. had this one redone and built to a 383 Stroker, nothing hot, new heads with good rockers, larger valves ,9 to 1 flat tops,little larger than stock cam, steal rod caps and good rods, Edelbrock perform, intake , shortie headers Holley throttle body,just a good strong mildly built motor and a good rebulit strong 700R4 tranny. the problem is, I'm not gettin full power from the motor, (Note* had a custom chip burnt with the specs of the motor, tire size, rear end the works and the motor runs worst) I pulled the return line from the tank and pinched it off and the motor seems to run better. Has anyone had any luck dropping in a 383 Stroker in a truck or car with the EFI? and what was your success? Like I said it seems to be a fuel problem , but could I also have some computer problem, apperciate ya'lls help on this. My wife is now callin the truck a "Problem Child"