So are the rear ends if not properly taken care of. Nothing serious just a lot of noise.
Along with the shift forks and clutch.
So best bet if you are going to take the engine out and aren't 100% on the condition of anything.... Better do it then as opposed to busting your butt on it later.
You can strip down an aspencade but you'll need to do a lot of frame modification in the rear to get it clean.
Cut some here smooth there and fill here.
It can be done.. and should look pretty sweet.