I have an 81 T/A with a 400 and th375 trans. Motor was rebuilt a while back and having issues with performance. It has none! 10.5/1 comp, 750  edelbrock carb (had a demon, that was worse), Performer RPM manifold, MSD HEI ignition, 2800 stall, 6X heads. Car is gutless. Guy that built it was "the guy" for performance. No idea the cam profile, he forgot. Runs hot, always near 200. What do I do?  

Run a compression test. With 10.5:1 CR and any reasonable cam, you should have 170-180PSI.  

If CR is good, get it on a chassis dyno to check and adjust A/F and timing.

2800 stall converter seems too high for a street driven car.  Remember, to get higher stall means more slip and HP that goes up in heat.  Personally, I'd use a 2200 stall speed.  You did not mention rear gear ratio.

Hope this helps.

Craig  

was camshft degreed,cam timing might be off.also ignition timing is something to look at.carb adjusted for altitude...just some quick ideas  

jrhinke

check the camshaft thrust plate - tighten bolts to 20 lb. ft. torque with loctite on the bolts - then camshaft will not move - timing stays fixed

67gto  

Not if the timing chain has jumped a tooth.  Of course this should not happen on a properly rebuilt engine with steel gears, but this used to happen relatively frequently with the old nylon upper gear.