3.0 or 2.9
#2
RE: 3.0 or 2.9
You mean 3.0 to 2.9 or 3.0 to 2.0 (as you wrote). 3.0 to 2.0 is a NO-GO. 3.0 to 2.9 - I think the years and style are too far apart but I'd start with a general look at the number of bolts that hold it to the engine and their arrangement and number of starter mounting bolts.