I recently swapped a 350 in a oem equipped 305. This is a 92 Camaro w/TPI. I bought 21 lb injectors for it and installed them with the swap. The engine is brand new and the only modification is the block is bored 0.040 over. My question is, do I need to change the PROM chip to a 350. If so, will the new PROM chip work in current PCM. Thanks for any help.

You do need to get another chip. It will probably run without changing the chip but you need the chip to compensate for the new injectors. As long as you get a 350 chip for that model PCM it will work.