Preuni

I am in the market for new heads for my 383. After extensive research I decided to go with pocket ported WP sportsmanIIs with 200cc runners. A machine shop in Vegas (dynoflo), which I contacted for doing the porting job strongly advised against the sportsmans in favour of proaction heads with 180cc runners. According to dynoflo these heads outflow even ported sportsmans and have way more low end torque......I never heard of these heads before, does anybody use them on this board? Is it true that the sportsmans are not suitable for marine engines?
My engine setup is as follows:
88`383 SBC, 5.7rods, forged pistons (4 valve dishes=12cc) cr. 9.5:1
Stock heads milled down to 72cc, large valves
CompCam XE 262 High Energy
EMI Thunder with stainless risers, open exhaust with slip in silencers
GM high rise manifold, Q-Jet 750, DA tips. I want the engine to be reliable with 400 hp and no more than 5500rpms.
Boat weighs 3500lbs with gas, 22 Foot Pachanga, with the above setup the boat unfortunately runs hardly faster than with the stock 270......(21 Mirage 60 mph 4700rpm)---very frustrating!
I had a topic on this board and everybody agreed that my limitation are the stock heads, which simply cant flow enough air with their 158cc ports to take advantage of all the other mods......although Dennis Moore (welcome on the board !) recommends to stick with these heads and modify them with large valves (which I did...)
My plan was to go with fully ported SportsmanIIs..... fully ported in order to increase port velocity at low speeds, I dont want the boat to be a dog coming on plane............
I would highly appreciate you board members advice before I spent the money for unsuitable heads,
and Dennis, if you are out there, thanx for your great book, it was a huge help selecting parts and building up my engine! I would be very interested in having your opinion on my problem here........
Thanks in advance everybody, this board is so great!
Andy

Dennis Moore

I agree that you need a little bigger intake port for your combo but unless your going to change your cam I don't think you will gain much by going with 200 cc intake ports. I like your combination as it is now and I think that 180 cc heads would work better but remember that you also need that large combustion chamber for those flat tops and long stroke to keep the compression in check. I don't know anything about the Pro Action Heads (are these the ones made in Australia?). Good luck with the changes but I wouldn't change much from the original modifications! I hope I have helped but I think you have thought this through pretty well already, you seem to be pretty sharp!
Sincerely
Dennis Moore

Preuni

Hey, Dennis thanks for the compliment, but actually its not my combination, it is one of yours.........the only sharp thing I did was buying your book....!

Now that I know, that the 200cc heads would be overkill I am considering stock vortech heads with 170 cc runners.....O.K., they feature small 64cc heads, but with their modern combustion chamber and the 98 Octane fuel we have over here I might get away with a cr of 11:1..... Even though I have to switch manifolds (and the choice on vortech manifolds is limited..) I am tempted to give it a try.....

Travis, I read in your post, that you want to step up to bigger heads in your SBC 383. If your vortechs incl. manifold are for sale let me know!