I've about concluded that a 4BT, perhaps tweaked a little - perhaps not, would work very well in my Sub. The 6BT's fit is a bit tight and I don't need quite that much power. My trouble so far has been finding one. I understand that some came already bolted to TH400's in delivery vans/trucks. If these exist one of them is what I'd like to find as I had to get the Sub's 400 rebuilt a while back. My trans guy said making it work with a diesel is mostly a matter of a diesel shift govenor and a diesel converter. Any pointers on finding one?