Wondering if anyone can help with a couple of questions? I have a 76 hallett with a 455 olds. I know nothing about engines so I would need a shop to do everything. From what I have read the 454 BBC is just a better engine then the 455. Right now the 455 is not giving me any troble but I just don't trust it, especially when I want some speed. I am wondering what I should budget if I wanted to swap it out for a stock 454 BBC. Also, someone told me that I would need to have the engine cover redone. The engine cover is the kind where it is in the middle and you have two kid seats next to it. Any help would be great.