I was wondering if it was necessary to completely remove the crankshaft to replace the main bearings. any input or experience would be appreciated.

 

Well, to even move it at all, the main girdle has to be un-done, rod-end caps taken off, rear main taken off, and oil pump taken off along with the t-belt and pulley. By the time you have all that off its basically sitting in there, so you might as well take it the rest of the way out instead of half-way to put the new bearings in. Regardles of how far you want to take it out, to even move it all that will have to be done, and then it will just pull out, so make it easy on yourself and take it all the way out. But, if your in a bind or something, you can do everything i said except take off rod-end caps and pull on the crank and pistons to give you clearance to switch the main bearings out.