I have an engine out of a 71 vehicle... it is unknown if it has been rebuilt(love Pick&Pull 1/2 off weekends:D)

I am going to go through the complete engine and would like to know how the hell I tell if it has hardened valves?

Obviously in CA, I'm stuck running unleaded but I'm also giving SERIOUS consideration to propane :p

I believe 72 was the first year for hardened seats which were required because of the change to unleaded fuel that year..

Is there a way to physically tell if I've got the hardened seats or not?

I don't have a clue what I'm looking for :p

dont quote me on this, but when you look on the heads, you might be able to see a ring around the seat, it means the seat was pressed in, and possibly is hardened. Myself personally I would take the heads down to a machine shop and let them check them out for you, and do a 3 angle valve job on them.

Most of the heads have induction or flame hardened seats. There is no pressed in seat. The only visual indication is if you can still see the discoloration of the metal around the seat from the heat. I have always wondered how deep the hardening goes when they use this process. Do you just cut all the hard metal away when you do a valve job? 1971 is close to the time that they started with the hardened seats, so it's a crap shoot.

well whats the engine?
That has a lot to do with it

for example International has been using hardend seats since the late 50s

Originally posted by Chief yelling alot
well whats the engine?
That has a lot to do with it


*coughs*Cadillac 472 *coughs* :D