aluminum heads ???

[glassdave]

i know this questions probably been asked like a milloin times,but what are the pro's and cons of aluminum heads on a marine engine.i'm runnin small block bout 350 hp,stock merc exhaust 4" through transom, open cooling, the usual stuff.i got a fresh set of GM late model,87 i think, HO heads i was thinkin of installin.and while i'm pickin your brains what do you guys think of pete jakson gear drives, can they handle the marine environment. thanks people

[superdave013]

If you want to know what I think of Pete Jackson gear drives check out this thread. http://free.***boat.net/ubb/Forum4/HTML/001320.html
I'll let some one else tackel the al. head question.

[77charger]

aluminum is the way to go if you want to save weight.but steel has the advantage in strenghth have heard that steel can hold more horse power also,
almheads pros-can run a .5 point higher comp on pump gas,lighter,dissapate heat quicker
cons- not as strong,can erode,warp easier,expensive
steel pros-can run a higher comp ratio(race gas)stronger,cant warp as easy,cheaper to buy.
cons-weight.
these are just my opinions and stuff that i have heard and read about.if it were up to me on my boat i'd go steel if your looking for small block chevy heads consider the dart 220 spotsman heads they are on my bros nova which is pushing almost 500 hp(dynoed).they are highly reccomended for built small blocks

[Jungle Boy]

Originally posted by 77charger:
aluminum is the way to go if you want to save weight.but steel has the advantage in strenghth have heard that steel can hold more horse power also,
almheads pros-can run a .5 point higher comp on pump gas,lighter,dissapate heat quicker
cons- not as strong,can erode,warp easier,expensive
steel pros-can run a higher comp ratio(race gas)stronger,cant warp as easy,cheaper to buy.
cons-weight.
these are just my opinions and stuff that i have heard and read about.if it were up to me on my boat i'd go steel if your looking for small block chevy heads consider the dart 220 spotsman heads they are on my bros nova which is pushing almost 500 hp(dynoed).they are highly reccomended for built small blocks

[Jungle Boy]

I run Air Flow Research head on my 383 stroker and have never had a problem with them. They work real good. Any weight you can save equals mph. As for more HP from steel heads. I don't see anyone running steel heads on river racing boats and some guys are pushing 1000 HP.

[wsm9808]

The only big advantage to an iron head that comes to mind right now is the inital cost is less. The aluminum will corrode easyer than iron if neglected, but all of us jet boaters take too good a care of our boats for that to ever happen to us. Aluminum can be easily repaired if you ever damage it with a dropped valve or such. But if you want a set of iron sportsman II, there might be a pair of good used ones in the back corner of my shop.

[wsm9808]

Which 87 heads do you have? Most of the iron ones will be the FI "swirl" port with swirl/curve in the bowl of the intake port. They work great at low RPM on a suburban, but they flow like crap above 4000rpm. Get me a casting # and I can tell. If its 191, 193,or 187, keep looking for another set.

[glassdave]

wsm,the casting # is 10088113.i cant remember
why i thought it was an '87 head, that may be wrong.i saw in a chev power hand book its an H.O. 350 assembly. all the intake bolts mount the old way,straight in and out ,not the 73 deg late style.is it still worth using? by the way im throwin in the towel on the gear drive thing, the link that superdave posted was enough for me. thanks

[wsm9808]

That should be an aluminum HO head with 163cc intake port and a 58cc combustion chamber and 1.94/1.50 valves with angled plugs and no heat risers. They are not a serious performance head but you can make some decent power with them and will raise you compression quite a bit over the 76cc heads. They where mainly used on the vettes, and will save you some weight over the iron ones. In my opinion performance wise they are better than most stock heads, but fall a little short compaired to small runner aftermarket alum heads.

[glassdave]

thanks wsm,that helps alot.i dont want to get to nuts with this engine,i want to keep it consevative for now.sometime in the future
(you know how this goes) http://free.***boat.net/ubb/rolleyes.gif i'd like to build a bigger motor ,maybe a blower or stroker.got no shortage of projects though. just out of curiosity what do you want for the sportsmans,you can e-mail if you'de rather not post price http://free.***boat.net/ubb/cool.gif