With the motor off,have a friend press the accelerator pedal slowly a few times to the floor while you are looking at the throttle linkage.If it is binding,you should be able to see while it's being depressed.
Also you really should get yourself a MSD Rev control ignition box instead of using the factory rev limiter.The factory rev limiter does the worst thing to a blown motor,it removes the fuel,causing a instant lean condition.The MSD box removes spark instead of fuel..
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Paxton Blown 87GT