That's the only part I was really keying on....

 

If u have 3.54 rear end a stock engine it will seem gutless. Turn power screw up 1 turn and that should make it a tolerable ride w/no more than your pulling. I wouldn't go any more than that until you have pyro and boost gauges
$

 

Allstock beat me to it, what's your gear ratio??
also, if that 124,000 mile tranny still drags the original torque converter, you may be losing quite a percentage of the engine power.

 

Tranny seems to be really good at this point. I'm sure once I am actually making some power it will really show how crappy it probably is.

It has 3.54 gears.

 

I vote on the converter. My 90 was doing the same before I yanked the trans from it. Towed fine with loads under 6k and anything over that t fet like it had no power.

 

My buddy has a truck mechanically identical to yours. It pulled better than his 97 1/2ton, but was still a dog IMO. Got the trans re-rebuilt (100K on rebuild, convertor went south), with a good upgraded low-stall convertor, and it added at LEAST 30hp at the wheels. No gauges, but it is a stock truck, complete with tammper caps and all (I did give him some more RPM for towing in 3rd). It still isnt a powerhouse, but it will outdo my mom's 92 with a stock convertor and fuel turned up 30%.

My vote is the convertor. If you have a tach, look at the RPM drop from 3rd to OD. May not be more than 100rpm. We are getting to the point that years sitting mean more than miles not accumulated.