Blazer/Jimmy engine swap question

I have a '99 Jimmy with a cracked block, and I'm about to pull the engine in anticipation of putting a used 4.3 L engine in. The tranny is in good shape. I wondered if someone could tell me what I need to know as far as engine number codes....like will only certain engines fit in there? Also, will any other size engines fit in a '99 Jimmy, like is there a 4 cyl. that came in these? I really just want to put another 4.3 in, just exploring my options. I am only going to use the Jimmy for driving to work in bad weather.

Any GM platform, (S, T, M, L, C, K, or G) 1998 through 2002, 4.3L "W" engine will work. If your Jimmy is 2WD, get an engine from a 2WD. If it's 4WD, get a 4WD engine, (less fooling around).