I have a '94 Blazer 4x4 auto with a dead motor and was thinking about just replacing it with a new one if I could find one rather than dealing with whatever is wrong with it. It has a 4.3L V6 Vortec in it with VIN W. Basically I am asking what engines will drop right in and fit without having to swap the transmission or anything like that. Or at least any leads to help figure out which engines will fit properly.

I'm not sure if this is in the right section since this is my first visit here so move it if it's wrong. Otherwise, thanks for the help in advance!

 

Have a read through this:
Rebuilding The Chevy 262, Doug Anderson, Automotive Rebuilder, March 1998

That should answer most of your questions.