Can anyone tell me how long aluminum heads last in a salt water application? I am in the market for heads and am on the fence between aluminum and cast iron.

1 year to 15+, all depends on how long it sits in the water, anode protection, good grounds, and how well you flush it. Don't bother with the hard anodizing. I have 4 sets of heads right now that are anodized and needed to be welded on the deck surface.

What do they do to OB's that make them so impervious to salt like everyone says?

Aluminum heads on a aluminum block is no problem .I believe the iron block in the mixture in a I/ O creates Electrolysis

I have always used cast iron heads and never had a corrosion problem so I know that's a safe bet.would hate to spend all that money on something thats only going to last a few years.most out boards completely drain out when they are not running but there have been problems with yamahas.

if you want to run aluminum, anywhere in salt you should think about fresh water cooling...eats the hell out of everything !

If i was in salt, with raw water cooling, iron would be my only choice.

Dart has some nice iron heads, 308, 330, and 345 cc. Engine Quest is casting the old RHS/pro topline iron heads, available in 320 and 360cc runners. Those would be my choices in iron heads.

you need to keep water temps under 140degrees and cooler is better.heads can usually go 4-5yrs if flushed after use and use Dawn dishwashing detergent at the very end.don't know why it works but it does.also use it on cast iron too.

that and they use a really good hard anodizing process,,most likely a mil spec one.

Just some info you might want to here all the merc 900sc and 1075sc plus a few others run aluminum heads and go many years. I have sent heads back to brodix to have them welded up on the water jackets and the price was very reasonable cheep enough that I would not do them. I don't know if the other head manufactures do this service but brodix does look into that. I don't think Brodix will fix other company's heads. If you flush it after use you should get many years out of them.