Update on this now... The engine is a 429 not a 428 I am sorry. I thought it was a 429 but wasn't sure. What are the pros and cons of a 429 and can I make reasonal power compared to a 460 with it? I have driven in this truck before and everything. It runs really good, all new parts, etc. The guy can roll doing 15-20 and punch the gas and it will still spin the tires. He doesn't have a bunch of hi po parts or manifold on it either, just pretty much built a little more than stock.