Looking for some suggestions.I swapped the manifold for a "B' and installed a 390 cfm Holley carb.The distributor is the later one.At idle and even if the rpm is raised it runs great(not being driven).I have vacuum of 19 which I think rules out leaks.Off idle and as speed increases its lacking power.(being driven)The more I push the gas the worse it runs.It acts like its lacking fuel.The filter is clean and fuel level in carb is correct.I had no problems with fuel pump(new late model) or ignition prior to swapping carb which makes me think it is a carb related problem.Timing is correct as far as what timing marks show.This carb has 512 primary jets and 54 secondary.Power valve is 6.5(65) and squirter size is 25.Motor is completely stock.If throttle is feathered it will build up power.I also installed a PCV system but even disconnected and plugged problem remains.The timing is advancing as it should.The only other thing to mention is that the phenolic spacer I am using is slightly larger bore size than the manifold holes so there is a small lip as air enters the manifold.Could this be part of the problem?Any suggestions on what to look for?The motor is a 292 in my 56. Thanks Mark