Jeff,
Timeserts would work great, but I just cant see doing them by hand. You either need to do them in a Bridgeport or a seat and guide machine to keep them half way straight. If people had any idea how bad they are from the factory, they would cry
It really is not all that hard of a job, especially if you take the heads apart first and get them clean. I figure no more than an hour and a half to do both heads.