GM-GMC: 1987 chevrolet 1/2 ton 305 throttle body, diagnostic check, emission controls

Question
my truck is lacking power under a load and wanting to stall out as well. i am thinking of replacing the hei in the distributor thinking that it may be a advance problem i am having. do you think i am headed in the right direction ?  

Answer
I would not replace the HEI without a full diagnoses of your vehicle's engine.

Spark plugs, spark plug wires, and the air and fuel filters are far more likely to be the source of your trouble.  Malfunctioning emission controls can also cause those kinds of problems.

I would start by performing a full tune up on the engine or taking it in for a full diagnostic check up.