HPT does not support LT1's unfortunately. Your problem does sound more spark/timing/ECU related, def check the opti and go from there. My friends car was doing something similar and it ended up being a clogged CAT fwiw. I have a MAF from my 01 if you need a new one, I'd imagine it might be bigger and you'd need a retune. I also think I have an old MAF-T laying around somewhere...