John DeBates interview raises good points. I run a one man (me) shop at a parts store.  I have kept track of actuall time to do a ton of different jobs.  I do it on almost every job, flywheels, rotors, 32 valve v-8 heads.  I send the time card with the job, customers can see how long it really takes.  Good repair shops see that I don't charge even close to what they charge.  If everyone did this on every third or tenth cylinder head, and priced accordingly, we would all be better off