I think like everyone else here wanting to do a swap is on the fence over the 4BT and the 4BD1T. I'm just seeing what my options are for a manual transmission, because I know a 4BT has a lot of transmission options. Could I use the adapter from the isuzu swap kit with a manual instead of a GM auto? does anybody know if they sell an adapter to a GM manual? I like the Isuzu because they seem to be easier and cheaper to find then the cummins, they're better on fuel and from what I've read they have just as much tweaking potential as the cummins. thanks a lot.