I do realize you are on a budget but you seem committed to a modern automatic and a new long block or donor motor factored into your budget.
You are committed to new motor mounts and trans mounts already. It's a good plan. The cost is all about wheeling and dealing and DIY.
Buy the stuff, take off front clip and mock up. Take your time and sit there with the mock up and make friends with it.
I'm needing the automatic because I'm going to hand controls only, my good leg ain't so good these days and the tonner clutch is a bit stiff. I love the smooth, quiet operation of the inline six, I can DIY a carb and points, and I don't want to re-engineer the fuel and cooling systems. A long block from a reputable builder would be preferred, because if I had the time or space to rebuild a GMC block
I'd do the running 248 that's in the truck rather than buy a second set of problems. I may rebuild the 248 later if the head isn't wrecked, I'll figure that out once I determine if there's a running block w/auto trans available to fill the gap.
There's a strong possibility this will be the last project I do at this address if I disassemble the truck in the parking lot. Eviction proceedings take around three months, I don't know if I can get the new driveline installed in time.
