Just looking through for some frame stripping tips and stumbled on this one - don't mean to kick a dead dog as old a post as it is..
Anyways, I sandblasted the engine on my 750F to hell and back, and I gotta say it worked great. If you're going to prime/paint it, I would recommend using sand due to the coarse surface it leaves. I just finished my case this weekend, during the unusually warm days we had this winter I'd put a coat on here and a coat on there, normally 2-3 weeks apart. After the second coat of primer (yes, I put down 2 coats), I was left with a relatively smooth surface, and after the first finish coat it was smooth as silk, like a new car.