I have been looking, I think inconel valves from Manley are $38 each versus 214N stainless. Stellite is hard to find, as is sodium filled (don't recall a price on those). Normal valves are $9 each, I think. Some say the edelbrock e-tec 170cc aluminum head is the ticket and valve seats live longer because of the conductivity of the aluminum head. The bronze valve guides help too.
That might be the route to take. Or an improved valve seat insert. Some of these stock iron Chevy (vortec) heads came with inconel exhaust valve seats in 1 ton trucks. So mercruisers might have them?
I have the heat exchanger FWC system. Holy crap, are riser extensions expensive! And yes, the engine sits LOW in the boat.
Nothing is broken yet so I will wait and maybe build heads next winter. I will just have to set cruise at 5" Hg to make sure I NEED new heads.
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