I have a 91 chevy and it had a 305, after flooding it I swapped in a 350 from a 90 chevy, I bought a jet performance chip for that motor. Now its throwing an engine code that says prom error... I know the computer is the right type... just not sure if there is anything I can do... it runs a little rought but do I just need to run it more?

I suspect that you need to change the other chip to one for the 350 also

from the title of this post i thought i was gonna see some pics of a high school dance gone terribly wrong oh well, good luck with the truck!

I'll take a wild guess and say it sounds like the checksum is incorrect on the chip. Have you tried it without the Jet chip? What's the computer part number?