Chuck.. sounds like there are many possible issues.
Ensure you have thoroughly cleaned out the fins of that radiator. Dirt can and does build up.
The heat and possible restriction in your exhaust could very well be what is holding you back.
As for fueling.. you might want to bump up your pressure a little to compensate for some of the mods. However.. I'm in no position to tell you where to put things based on your mods..(or my lack of experience