I am putting a 460 into my 73 250. I have a bellhousing from a 78 400 2wd and a flywheel from a 360 w/a new diaphragm style clutch. The trans is a NP435. when i went to put on the trans, the input shaft bottomed out on the pilot bearing. so i went back to the 360, got out the old bronze bushing and took it down a bit on the grinder so that it sat 1/8" below the face of the crank. I bolted everything together and put it in the truck, but when i tried to start it, the engine was bound up. But by loosening the four trans bolts a little, i was able to turn it over just fine.

I don't know if my bellhousing is too shallow or if i need to tear apart the trans and modify the input shaft. I thought that this was a very common swap, but i've never heard of anyone having this problem. Although, most of the trucks that i've seen had c6's behind them.

Any help is appreciated. TIA

 

See this thread and the engine swap forum.
https://www.ford-trucks.com/forums/s...d.php?t=463467

There are other posts around on the subject also.