Those are nice numbers for a N/A marine 540, especially on a conservative setup. I love the fact it has 305 AFR heads on a 540, and a conservative cam, low compression, and still make good numbers. Not to mention dynoed in full marine trim.

No reason at all , they are good heads also . I must say that i have never heard a single bad thing about AFR's and plenty here use them with great results .

After reading your remark I did a search on Google to see what you are talking about, I searched "AFR heads thin casting" Out of 2 full pages I found several hits but when I opened the links they were NOT saying afr's were thin by any means, they were actually praising them for outperforming most other heads of equal port size.
I DID find found 2 different post on 2 different forums where someone was claiming the were cast in china and thin, 2 totally different forums BUT the same guy posting, "LUKE FROM SA", I think this guy is very seriously misguided, there is NOTHING wrong wiith afr heads and they are built very well, Smitty
HERE IS A LINK TO THIS BS:
http://forums.corvetteforum.com/c3-g...-afr-dart.html
"AFR will outflow a lot of other heads.
But.. Be aware that they are cast in China and finished machined in the USA. A BULLSHIIT LIE
They are are a thin head casting and not often seen on true race/high HP engines. EVEN WORSE BS LIE!
Very good bang for the buck.
I personaly believe that DART heads are a quality item, and made in the USA.
This would be my first choice.
I have had a few of each over the years.
I like the price of AFR but the long lasting quality of USA made DART heads.
You may notice that i'm from Australia.
I have done a lot of research BEFORE sending my $$ overseas.Tons of different heads out there for every budget.
Also cast and finished in many different countries. "
TOTAL BULLSHEET

Wow , what could possibly be the reason someone would post this kind of bullchit or worse yet , believe it . If you really want to know the truth go visit AFRs website or better yet give Bob Madara a call , he is an AFR dealer . Bob is also the best marine cam designer bar none . 585-654-8583

As stated nothing wrong with either head. Dart intakes flow better and AFR exhaust flow better, pick your poison. There is a recent thread here on OSO that someone just bought a new set of AFR's and he did have to have machine work. It was either resurface them cause they were not true or something about a core shift. It's manufacturing and whether we want to believe it or not there is always that 1or2 PPM that gets out the door. This is the only account I have ever read about AFR's. I would not hesitate to buy either I run Pro1's.

Edit: I have read about some Dart head bolt holes not lining up with the intake manifold and needed to be elongated or opened up. Later found out someone was selling blems... as new heads.

What cc piston did you use to get the 9:1 comp?
Lets say I ran same configuration as yours haxby but 9.5ish compression, what piston would give me this compression assuming I went the afr 305's?
Are any of the dressed head packages offered by manufacturers eg. Afr, dart, brodix any good or am I better off buying and assembling it all individually?

Hi Kurt, I'll get you all the part numbers when I'm back in the shop. For the best pricing and customer support you should contact RMbuilder on here, Bob Madara. He can spec and order your heads completely set up ready to go for your application. AFR's tolerances are excellent and you can just bolt 'em on and go. He can set you up with any of the other components that you need from this side of the world too.

The heat exchanger is from SeaKamp

Mr. Madara will assemble the proper heads for you with all the proper components and design you a cam to achieve your goals all at a price that will surprise you . He has always been more than happy to answer any and all questions you may have . Good luck on your project .

Hi Kurt, they were a flat top that poured about 3cc on the valve relief. The smallest dome on a shelf piston is usually 10 or 12cc. That'll put you 9.75 to 10ish depending on deck height, gasket, etc. If you plan on running low octane then I'd leave it around 9:1 to be safe. The half point probably isn't worth the risk for the very small amount of power it might be worth.

Thanks haxby
I definitely don't want to run anything other than pump gas. Like I said before the best we have here is premium 98, which is the same as your 93. I'll stick with a flat top piston
I had a look at the seakamp heat exchangers online. It says the kit is rated to 500cid, how does it go on the 540 with long periods at speed?
Thanks again for the input.