I have a 91 4.3 chevy tbi w/700 r4, and i have noticed that i have no real power with the truck. I have adjusted the timing and checked all the sensor and wiring harness and even gave it a complete tuneup with all ac-delco parts.

Here is my question, I was wondering if i can take the factory computer controlled distributor out and replace it with an HEI dist. Will it work or will it mess with the computer as far as fuel control..

Quick answer, no. The injectors get their timing pulse from the ignition module.
If you are low on power check your fuel pressure.

Will