Question about engine swap on 3.4
 

I have a 97 monte with he 3.4 and a major engine knock that I'm wanting to fix. I have another monte that's a 95 that also has the 3.4 and was wrecked and I was wondering if everything would be the same. I saw something about the 95 not being OBDII so the wiring would be different but I wasn't sure. Also, how difficult is it to pull the motor? I've pulled a few motors but never in a car like this. Thank you.

Unfortunately, both 3.4 DOHC engines aren't exactly the same; there are a surprising number of differences between them, in fact. One of them is the OBD-1/OBD-2 difference you already noted. All their parts aren't interchangeable; they have different manifolds with different port shapes, heads, sensors, probably different powertrain control modules too.

If I were you I'd just try to fix up the '97 engine without swapping anything.