[jackyandjoe]

I have a pair of chevy heads 427 1968, someone told me i needed to change the Valve Seats to prevent from damage due to the unleaded fuel in now days. Do I have to change all 16 of them or just the exhaust ones. Thank you.

 

[tresi]

If the intake valve seats are in good shape you would only need to put hard seats in the exhaust.

 

[Robinson Robin]

Weather or not hardened seats are necessary is some what controversial, do a search for previous threads on it has been discussed at some length

 

[Canadian Charlie]

I'd replace all 16 if it was my engine

 

[Robinson Robin]

I'd replace all 16 if it was my engine

that would accomplish very little besides lightening your wallet(unless of course the valve seats are very receded)