[mrolds88]

427 will work. Or even a 454 out of a pickup would be fine too. Get a late enough model to get the TBI and take everything that you need for the conversion. Also ditch the 545. if you want to keep an automatic, go for a Allison 2000 or 2400. The 545's were good transmissions, but they dont lock the converter and they keep the rpms up. Actually I just had a thought. Every once in a while you can run across a fleet truck for sale (schwans and ryder comes to mind) that you might be able to do a whole drivetrain swap from. Engine, trans, rear. Plus sell off extra stuff from what you dont want.