Keith and SD, very balanced "high-road" messages.

I don't have any ported numbers on the new heads yet, but I did find the ported numbers from the stockers when I was at Innovation. Intake valve 2.250 ex 1.820

Lift..............CFM...............Exh.CFM

.2................157.................141
.3................230.................190
.4................292.................221
.5................330.................238
.6................348.................249
.65..............353.................251

These heads made 600hp(dummied down to 590) and ran on one of the bat boats in 06. They used the stock intake manifold and I believe a modified airvalve.

The iron eagles will flow more air with a 2.3 valve, very close to 400 cfm @ .700 lift

Can the heads be bought from some dealers for cheaper than the $689 each/bare from Dart? Or are they only available from Dart at this time?
Thanx.

I can check availablity and let you know monday.

Can you also ask them if they are direct turn key bolt on replacement for the Mercruiser 496HO heads including all Merc attachments and accessories?

The Dart 8.1L heads are direct bolt on replacements for 496 Mag and HO heads but they will as you already know require some different valve sizes and such as they are not set up to accept stock 496MAG &HO (GM valve sizes). I believe the rocker studs and guide plates transfer over as well as valve springs and retainers especially if you already have aftermarket sizes. My guess is that if you finish these bare heads complete with proper valves and parts or buy them from Dart complete you will end up spending right around $1000 per head or about $2K per set, plus your head gaskets costs and head bolt kit costs at around $400 per pair for those who want to know.

Best Regards,
Ray @ Raylar

That would be cool. Thanx.

8.1 heads
 

I talked to Dart today. They said the heads were 26 heads that are being machined and sixteen were spoken for. Orders are being accepted. Jobber price is 654.00 each bare. All holes are in the heads for marine and are targeted for the marine world. Also he mentioned you shouldn't need any add ons such as longer head bolts. I didn't ask about valve guide size and if the stock valve springs would convert

I was at Dart last month and was able to talk to Richard about the heads. Very nice, I saw a dyno sheet of a motor over 800 ft lbs of torque. Also they have a very nice looking intake manifold with injector bosses (dosent look like a coffee table sitting on top the motor)

But if you already have all the valves and valve train hardware it is a sweat deal.

So these heads are not dedicated for power generator station rebuilds as Raylar said? It has been reported that the valve stem guides are for 11/32" dia valve stems instead of the stock 3/8" dia stems. Say it is not so? Will the stock valve stem length and springs work in these new heads or not?