Dead Computer?

1988 Chevy Caprice Classic Wagon
5liter V8 - 307

Just took a long drive from Salem, OR to California City, CA and back.
Car goes slow uphill because no torque, and on one of the last hills down past bakersfield my check light came on.
Didn't seem like it was really having issues but on a cold start it sounds like I have a misfire now.

Took the car in to have the codes checked and the guy was unable to connect to the car, couldn't even jump it with a paperclip to see the light flash, says my computer may be dead.

Attempted to disconnect battery to reset the check light and when reconnected, check light comes back on immediately.

Any Advice? Suggestions? Ideas?

Thanks guys!

Rip out the computer and convert it to Canadian no computer 307 specs?

http://www.karlperformanceparts.com/p/350-290-300HP-Crate-Engine-Chevrolet-Performance-12499529/1891?gclid=CIyF2Mzhvs8CFZaIaQodOMMBpg