Still up in the air about heads
 

I've decided to upgrade my my heads over the winter to the dart Iron Eagles, but the question now is which one? I need the 64cc chamber, but what size intake runner? I haven't found any answers online. I also need to know if my cast iron high rise manifold will fit. It's a chevy 383 with an XM-262-H cam. Any Ideas? 180cc? 200cc????

Re: Still up in the air about heads
 

What are you looking for most,Top end rpm or midrange?If most your driving is 3500-5000 the bigger heads will only hurt you,if your going to buzz it to 6500 (not usually what most people do with long stroke small blocks) then go with the 200's.Iv'e used ported 180's on 355 smallblock limited late model engines in circle track cars and we buzzed them to 7200. Your cast iron high rise manifold should fit(check port alignment),sometimes you need to use felpro or mr gasket intake gskt's that are .120 thou thick to get intake to sit on heads good.Your cast iron high rise gm intake has short wide port openings that will be closer to lining up on the 180's also. Another thing is if you were going to use a higher flowing head like the 200 you would be closer matched to use a open plenum intake. For better upper midrange and fuel distribution i have cut 3/4 by about 3-3 1/2 inch out of center of plenum divider on gm cast marine intake or use a 1inch phenolic resin spacer under carb if you have hatch clearence. Good luck,Smitty
After re-reading your post and seeing you are going to run a 262 advertised duration comp cam,I would definately lean towards the smaller 180's,the gm vortec heads would almost be perfect for what your doing but the port alignment would be a nightmare(the vortecs have ports opposite of the marine intake ,tall and narrow versus short and fat) and would require welding on your intake to get it to seal(been there done that)

Re: Still up in the air about heads
 

I was figuring 180's would be the way to go. I do most of my cruising at around 3500, with the occasional top end blast, but right now the engine seems to run out of steam at about 4600rpm with a 21" prop at close to 60mph, or 4900rpm with a 19" prop. The fuel system is fine, and I've already played with jetting, I just think it's the stock heads holding it back. I was thinking about the Vortec heads when I built the engine, but I couldn't find a performance cast iron intake for those heads, until now. I came across a site yesterday that specializes in cast iron performance heads, and they sell a cast iron high rise for the Vortec. http://www.castheads.com/heads_folder/1heads_set.html
I'll probably go with the Iron Eagle 180's unless you have a better suggestion. I can have my friend who does head porting, go over them, and port match the intake, and do what ever else needs to be done. As far as the intake goes, I was thinking about using the spacer. Do you think that will do anything for me, or would I be better off opening the plenum divider? I have plenty of room under the hatch (enough for a blower!):)

Re: Still up in the air about heads
 

Try www.cfm-tech.com They have a vortec MPI intake that we are going to throw on the 350MPI in the deck boat if we don't put a blower on it. They do some pretty nice things with cast iron intakes. I still think the 200cc heads will be fine on the 383. THat thing has so much bottom end to start off with it could bog and still beat most 350s out of the hole. Well mine anyways :D

Re: Still up in the air about heads
 

Now your hinting on a possible blower in the future? cams are cheap but heads ar'nt. I would go for the 200cc now. Or wait and save some money for the blower and buy it all at once, then use the dart pro 1 aluminum heads with a Whipple. 383's love those heads.

Re: Still up in the air about heads
 

I'm kidding with the blower:)
I'm looking to upgrade in a few years to a 24' (Haven't decided what make yet), with a big block. Then I'll start thinking about a blower.
Right now though I just need to decide what heads to buy for my winter upgrade.

Re: Still up in the air about heads
 

aero-offshore,Liberator 21 is going to use a comp 262 cam,we are talking 218/224 at .050 and 460 lift,(small),i'm also going to asume he's using stock exhaust,all the bigger runners will do for him is take power out of his cruise rpm's! I think the 180's are plenty big enough,if he was talking 3 sizes bigger cam,more compression,radical exhaust,open plenum intake,I'd agree but based on his info and combo i wouldn't get too crazy with the heads,my .02,Smitty

Re: Still up in the air about heads
 

If Liberator 21 is like the rest of us he will want more in the future. If he uses the 180 CC runners now this same conversation will come up and 200 CC's will probably be recommended. If it were me, I would go with the 200's. The midrange will still be better than stock and then he is set for the next set of upgrades when he wants to go faster! My .02!
Craig

Re: Still up in the air about heads
 

"Still up in the air about heads"


Liberator 21, Does this make you an Air Head? :D

Couldn't help my self, you left the door wide open for that!

Cant improve on Smitty's advice! although I would like to add. Spending allot on heads that flow well, don't overlook a good flowing exhaust!

Bryan

Re: Still up in the air about heads
 

Yes I am! Hey, I've been called worse:)
As far as being like the rest of you (wanting more speed), I always have been! From as far back as I can remember. Just ask my parents!
As far as my engine goes, This is the one currently in my boat. I'm thinking the 180cc because I'm using a dual plane intake, and stock center rise exhaust. I'd like to get as much as I can out of my current setup without going too wild, because my plan is to find a 24' boat in a few years that needs an engine, then I'll build a nasty big block:).
Do you think the 200's would hurt the bottom end/ midrange that much?
Also does anyone know the size of the runners on my current heads? (Casting #14096217)