We put them on a Gen VI block lasted 60 hrs. the heads all eatten up from the underside (gasket side ) they should be better on a Gen IV Dart or Bowtie block. They all have round cooling passages in the block !!!!

What's wrong with the current heads?
The Ede. heads don't flow that great and I agree on the aluminum...for a salt water off-shore deal you're asking for a maintenance night mare, IMO. A set of well prepped large oval GM iron heads like a set of 781's or 049's will offer plenty of performance for your 454 as long as you can live with 118-119cc chambers. The GenVI block is compatablbe with Mk IV heads, it's the GenV that has issues.

READ THE POST,eats up the uncoated part of the head,ON ANY BLOCK

So what heads do you recomend to make more power than stock 500hp heads.

you running thermostats?al heads need cool water or they get eaten up quickly.i've welded my share of heads up because of the porting to them.

I have built a 2 496s and used the oval edelbrocks with 110 ccs to bump up compression. Are they the best head, NO, but for the price and with valves its a good option.

They will work on any Generation engine, you just need the correct head gasket.

I would use them again.

cleaned up hp500 heads,work them a little and throw acam at them and your at 600hp.

salt water in the block and heads? how many people run raw water cooling in big blocks? i can see it with small blocks. they are throw-away motors. and can tolerate a couple years of salt. but from what i hear no BBC head stands up to salt.

if you want your aluminum heads to last forever in salt water,install closed cooling system.there you go,FIXED

Yes gen iv heads will fit gen v & vi blocks but you must use the correct gasket .gen v heads dont work on gen iv blocks. Dart offers a coating to put on the heads that will prolong the corrosion,and flushing is a must. You might check out the exaust seats make sure they are harden soft street seats dont live long in a marine motor. And yes closed coolong is the way yo go.