'86 IROC drivability problem

I have imported a 305 Z28 IROC engine into my Jeep CJ5. Other than bored 40 over the bottom end is stock and other modifications are as listed. K&N filter into large breather tube to MAF. Exhaust ports enlarged matching 1.75" tuned headers to split freeflow 2" mufflers and 2" throughout rest of exhaust. Cam is: final lift .420/.432 - Duration @.050 208/214 - Overlap 64*.
I had some wiring problems initially then installed a Howell wiring harness eliminating a 'floating ghost' ground problem nobody could find. Before that was done it intermitantly ran like it should with plenty of torque and HP. Enough to pretzel 2 drivelines and splinter u-joints (oops). Now that the trouble has been rectified it is sluggish and relatively non-responsive. I associate it with a non-conforming eprom. Am having trouble finding someone to burn a custom chip and also concerned this is not the only problem. Any body out there have info or ideas?

dont really know much about mechanics but have u checked to make sure u dont have any wires on the headers or anything of that nature that could be causing them to arch