I was looking to buy some used heads so I can port them out and I found some from American Camaro for $195 with 85k miles on them. My question is what kind of shape do you think the average set of heads will be in after 85k? Do you think the valve guides and seats be ok?

 

If your going to port them out and run higher RPM, I'd just get new guides or guide inserts. As for valve seats, they are probably "ok" but if your going to drive it hard, it can be an issue of is it really worth it NOT to get them. Check for sunken seats and make the decision. Valve guides can be knurled "back to life" if you want to avoid using a better bronze guide insert, but they are cheap so it just seems like a wise decision especially if your going to rev the car out a bit. You will of course want new stem seals of course as well, expect that your basically going to rebuild the head, may as well.