Ive worked on a few cars and always done my own mechanic work on my own vehicles. But I've never replaced an engine. Ive rebuilt the top of one but never pulled thing whole thing out. How hard would it be to replace an engine in a 1997 blazer ls?

 

I think these are considered pretty complicated to remove, especially if you have a 4wd model.

I pulled an engine (when I was much younger) but that was on a 71 Dart. Much more room in the engine compartment!

 

IMHO it would mostly depend on the space and the ability to leave it in any state of disassembly.
Possibly in a heated garage where you can work during the winter.

 

This. It's a pretty cramped area you're working in, and the front axle makes it even harder to reach some of the things you need to. A decent backyard mechanic should be able to handle it, but be prepared to use some foul language.

 

(It's one of the more difficult ones, but most anyone with patience, determination, at least some experience, and a full set of hand tools can get it done. Is yours a 4WD or 2WD? Are you in a rusty climate? Thinking about used engine or a rebuilt engine? We can help you to peel a 4.3 out of a 1997 Blazer and then get it back in right! Best done inside of a garage on a cement floor with no rapid deadline so you can simply walk away when frustrated and come back later.

Several ways to approach it. Primary issues include getting to select bellhousing bolts, getting at other things bolted to the back of the heads, not bending things up, and oil pan to front axle clearance on a 4WD while leaving the transmission in place - finally and most importantly, where everything goes and in what order things go back together (lots of cell phone photos).