Cracked the exhaust seats on my cast 454 Magnum heads. Looking for a good replacement suggestion, Al or FE.

Mark IV, Gen V or VI ?
Where are you located ? Shipping cast iron behemoths matter $$$ wise by how far.

Closed cooling? Fresh water or salt?
Used or new?
Used, Sick Stinger on here would be the guy

SE PA. Not sure what Gen the block is. They are rectangular port heads. Guy i bought it from said it was the Mercruiser 365 Mag 454

Fresh Water, may see salt once or twice a year. Looking for new if possible

Is ADK61 still around? He was selling complete heads well set up for marine use. I believe the feedback was consistently positive, which is rare in this industry.

If it has a fuel pump mount location on the engine block, it is a Mark IV.
If it does not and has stamped steel timing chain cover, it is a Gen V. Also if the head casting numbers end in 088, they are Gen V.

FE = Engine Quest heads (direct replacement)
AL = Promaxx (economical good aluminum head)
Get in touch with JimV on the board and he can set you up.