It might be too late, but if you find the right suburban/pickup you can take the entire frame and drivetrain with the BBC. The 454 will make the torque you are looking for with a few minor modifications. A later year model will net you fuel injection and a 4l80e as well. If you do it right you can sell your small block and get your frame, 4x4, and BBC and make some money.
I have a 98 2500 w/ a 454 4x4 long bed reg cab. Want me to measure the wheel base and stuff for you?