yep, the two rear mounts are with the tranny and only one in the front which is basicly two side by side bolts almost under the harmonic balancer. I have the cab off, so I won't be worried about bending the floor pan or anything. It's a 51 GMC by the way, and sounds exactly as you've described the 53 being. I have a tractor with a frontend loader on it, planning to pick it up with that with a chain bolted at some strategic points.
