wow, didn't think Id ever see the thread again. lol

 

This technique is so old that it's new. The factory shop manual for my 1962 Pontiac Catalina showed rolling in a new main bearing using a bent cotter-pin stuck in the crank oil hole. The only thing that can stop you from installing bearings this way is a main bearing shell that has a pin at the top to keep it from turning.

Actually, there is even a way around those but I don't think I would actually do it on my own car because it involves hitting the old bearing with a chisel and breaking off the pin first..