so I don't get much power after 4500
Of course the accelerator pedal is more sensitive....................... Only "problem" is that it is difficult to maintain steady rpm without load. Idle is fine, but if I press the acc. pedal on neutral gear, the revs keep climbing even if the pedal is held steady. But I don't see that as a big issue.
Black Smokin' Diesel I shimmed mine that much and it ws way to much. It overfueled it way to much to early. It seems get rid of the intermediate spring then shim the main spring just a little with 2 small washers works the best for me.