well it appears they have had a lot of work done to them .i am taking them to get them checked out tomorrow to see how much but from what i can tell stainless valves and bronze guides and a lot of portwork.i dont have anything to measure them with but i think the valves are bigger than what the originals were.so that is the only reason i was thinkin about puttin them on.I figured they have got be better than the stock ones on my car.It may not be worth the time but i got them in a deal really cheap so just kickin it around!