I rebuilt my th350 with a Huges Performance kit and installed the new bushings that came with the kit.
Here is the problem:
When I went to put the pump assembly back in, it went in real hard, like the sealing rings or the bushings were really tight. It went in all the way, but I cannot turn the input shaft with my hand.
Is this OK?

 

The input shaft is usually hard, if not impossible, to turn with only your hand. I use a pair of Vise-Grips to turn it and check end play. The pump should go in easily. If not, the pump halves may not be aligned. I use a small block Chevy valve stem ( or 11/32"
drill bit) to align the pump halves, then tighten a large hose clamp around the body, and tighten the bolts. I put the seal rings and o-ring on the pump after I fit the pump to the case and set the endplay .