SBC valve seats.

Can anyone tell me if a 1973 SBC. had hardened valve seats?

 

yes and no

 

you want 75 and up to be shure or just have heads redone and have them installed

 

If I remenber right leaded gas was being phased out in '73 and cats were on cars in about '75. If it was me I would have them installed to be sure.

 

I think if it has peanut spark plugs it has hardened valve seats. They take a 5/8 socket. The larger plugs that are 13/16 socket would not be hardened.

 

They would be induction hardened seats that are part of the head itself, not separate seats set into the head. These have some funny coloring around them when cleaned up from the effects of the heat.

 

The hardening isn't all that deep though so if the valves have been done before the hardening may be pretty thin.