This car sounds like it has been modded a little... get a picture of the motor and post it up... I also drive an '86 GT... I just rebuilt my motor... there are a few flaws in the design on the 86... the engine uses speed density as apposed to mass air, so an aftermarket camshaft needs to have a similer duration to stock in order to keep manifold preasure up... if you dont choose a cam this way, you will most likely have BAD idle problems... the other thing to worry about is changing heads... the pistons on these do not offer clearance for larger valves... honestly, if you want better heads, look at powerheads(do a google search on em)... or look into a stock 88-93 E7 casting... im running an e7 casting on the new motor with extensive port work and they work GREAT! the other thing you will want to get done RIGHT away on this car is rear axle gearing... these cars come with a REALY crappy 2.90(?) gear in the axle... even 3.55 or 3.73 would be much better... ****! even the 3.08 fro 87-93 would be better! good luck!