I would have a look at the PTK linkage and make sure it is not keeping it from getting a FULL WOT.

I kicked myself for finding my truck would not pull any thing over 3500 rpm once. I tried a bunch of crap to find I goofed the linkage adjustment.

worked by hand under hood as I did not ever blip it fully open to see it. found it with a helper on the pedal while I watched and adjusted it out.

surly not your issue but thought I would mention it as I did not see any comment about throttle/PTK adjustment check for a full throttle.

the one piece rods on the trucks suck for adjusting and I swap them to a nice 3 piece set up.

my 85 runs a stock q-jet-intake/1 piece linkage set up and easy to only get 3/4 of throttle with it if not watching it.