I'm looking for suggestions on upgrading a 509, It's going to need a bore due to minor watermarks in the cyl's, It's running a 256 blower w/superchiller and 6psi boost, 2 750 holley's built by nickerson, 525sc cam, flat tappet w/roller rockers, 502 bowtie heads rec. port, thinking about alum. heads and cam upgrade, but water ingestions seems to be a problem, It was disassembled for a blown head gasket between #5&7.
what is a good alum. head that will perform well but not break the bank, this boat gets run about 10 hours a year.
Thanks
Larry

What type of headers are you using?

it's running the Imco version of gil's with std length riseres, wet exaust.

If you aren't already, make sure you use head studs when you put it back together. Also make sure to use Fel-pro MLS or similar head gskts. I have a Crane 731 roller cam for sale (Gen 6). It was on my 509's and with 8 lbs boost made 750 hp.

For an off the shelf cam, I'd use the 525EFI cam(Crane 741 on a 114 lob sep). Depending on if you change heads, you may want to go with a custom grind.

is the crane 741 a roller cam, and if I go with alum. heads, what is a good head for someone on a budget, is the 502 mag rotating assy, going to be OK for this engine.
thanks for the replies.

does arp make a stud kit, this is a mark 4, will a cam from a gen 6 work, does the cam have a lobe for the fuel pump, do you have the lifters also.
thanks, larry

Gen 6 cam will not work. You have get one for a Gen4.
Pro Comp aluminum heads are nice for the money.
$700 a pair with guides and seats or edelbrock marine complete are around $1500.

Yes, its a roller cam. As far as heads, I'm no expert. I have read the merlins really are not very good w/o some porting work. You get what you pay for. I would probably go with some AFR's. The Edlebrock Marine heads are pretty decent too and a good bang for the buck. The are what merc uses on the 525EFI. A friend made about 800hp with them on a whippled engine.

AFR's 315's $2800.00 a set , But you will love the power.