I am building a 383 for the boat this winter. Will be built for torque, max rpm 5000. Any recommendations for cylinder heads? I want to keep the compression to about 9:1, squish about .040.  

Vortec heads would be a fine choice. Any 170-180cc aftermarket cylinder head would be great...  

I do have a set of the new small port bowtie vortec heads. The have 65cc combustion chambers and 175 cc intake runners. If I use those I would need a dish piston of about -24cc. I want a good squish and do not know if I could find a D dish piston that would work?  

Check out Keith Black for a hypereutectic piston with a d-shaped dish. PN KB-102030, you will have to live with an 18cc dish. I see no problem with a cast piston with low-rpm, no nitrous, and low power but if you do want a forging for some reason there should be some $700 pistons out there with a d-dish for you. I'd check CP, JE, or Lunatti...  

those bowtie vortec heads will work great for your application.perfect runner volume for your rpm range.go to srp.com for online catalogue for small block pistons.  

Thanks. I am thinking of using 6" rods. So on the SRP page( http://www.jepistons.com/cat/srp/auto/chevy_sb/350-400_inv.shtml ) I only see pistons for 9.8cr. However on the page for forced induction ( http://www.jepistons.com/cat/je/auto/chevy_sb/extreme_duty_23_inv.shtml ) they have a piston that would give me 8.8cr.
Are ther any concerns going to a 6" rod for this my application and are there any problems running forced induction pistons in a non forced induction motor?  

Going to a 6" rod is actually a better situation, the word better here means ALMOST insignificant but I think it is better...

The only difference I can see in a forced induction piston COULD be weight (crown "thickness") and probably ring pack location. Now, these differences are negligible to everything but a max-effort build so if it's your only choice go with it...

But, I think I have some more pistons for you to check out if you wish to do so...

JE-170817-8 = 28cc dish, $750 from Summit
KB-734030-8 = 18.6cc dish, $460 (forging)
SRP-138103 = 18cc dish, $580
KB-164030-8 = 19cc dish, $275 (hypereutectic)  

The JEP-170917-8 with the 28cc dish looks like it may be the answer. Hmmm, now for a cam to go with the heads and piston. I am looking at the comp cams extreme marine http://www.compcams.com/Technical/Search/CamDetails.asp?PartNumber=12-416-8
???  

That would be a great cam choice. It will pull plenty of vacuum and be well-matched to your rpm range. Kudos on going with a roller, it saves a lot of hassle to not have to worry about flat tappet break-in and life expectancy.