[blykins]

What bellhousing/trans did you use?

For instance, if you used a TKO with a Lakewood without using a short input or a spacer plate, you could have jammed the input shaft up into the butt-end of the crankshaft, which pushes the crank up against the thrust bearing. With enough force back there (pulling in with the trans bolts) you could really foul the crankshaft against the bearing.

When installing a new engine/trans (with aftermarket parts), you should always measure the input shaft length from the flange and compare it to how much room you have between the bellhousing flange and the end of the pilot bushing/bearing. You should also turn the engine over and make sure it turns as free as it did with no trans bolted to it. In addition to that, I usually knock the trans out of gear and insert a slip yoke into the trans. With it out of gear, you should be able to turn the engine over by hand and hold the slip yoke without much drag whatsoever.