alum heads

Ok in the performer intake thread there is talk about alum heads. I thought it was brought up before and the general feeling was they were bad stick with cast iron. There was mention of the heads and the block being different metals and how the heads would react being around all the water. So which is, are they a good or bad bolt on. They are more efficient but will that make up for the problems some believe they would cause. I am asking because I had mentioned alum heads before, for the 454 and I was talked out of it.

it's not a good idea because of the heat range and thermal expansion, not because of dis-simular metals. Boat motors run cooler than car motors and with the different rates of expansion it's not good using AL heads on a cast iron block. If you had an AL block in your boat then it would be fine.

those are not aluminum they are cast iron, read a little closer next time.

79..Dont you have a set of Edelbrock heads for your boat? If its not a good idea, why are you doing it?

If you opt for closed water cooling, I'm certain it solves the corrosion and temp, but then you cover up that pretty engine with ugly plumbing.

Alternatively, I've wondered if zinc anodes in the right places, checked and changed frequently, could stem the dissimilar metal corrosion, but its a pretty expensive experiment.

behl,
those heads will really wake up your motor, but you need to finish the job you start. That will include A GOOD INTAKE ,A GOOD CAM,UPGRADE IGNITION SYSTEM.
This will give you the best bang for your Buck............ boat dr     

Its the corrosion factor that im thinking about, did you ever look inside a used Alum intake, it dont take long for the corrorsion to start!

Behl, GT-40s on a 302 could be a beautiful thing, with the same fitment as for a 351. However, if replacing a good set of 351 heads which were used on most 4V 302s from 71-76 or so, you won't see a huge difference, as those were the larger valve/small chamber heads. The heads used after that date, or basically heads with the small 5/8" plugs, have smaller valves and larger low compression chambers and were used on both 302s and 351s from about 77 on up. Check to see which you have. Those are the engines that really love the GT-40s as you get the nice boost in both compression and flow.   But if you're in need of a rebuild I'd go for them along with a flat top or dome piston and you will certainly feel the power. And there are tons of good intakes for it as well, and cheap, basically the same model names as for the 351s, i.e., Performer, Performer RPM, Weiand, etc., just get the 289-302 version. I'm currently running the Edelbrock RPM version and it's great.

Oops, I started typying, stepped away and more questions were asked before I could post. Doc, I've got a cam for Behl that will work soooo well with that 302, along with those heads, along with that intake, and so on. I've got it in 3 boats and you can get it from NAPA if you want. Clevite sells it and Jim-in-Houston (where is he?) has one as well. You can query the Clevite cam spec sheet that someone posted way back when and find it.     

Steve, I just updated my post slightly to inquire as to which size plugs you have as well as a cam note.

I would say the only issue with aluminum and cast iron would be a problem with head gaskets not sticking very well.

I guess we are at a cross road here, some say yes to alum heads others say no. Not seeing the difference between a closed system full of anti-freeze and an open system running lake water. The alum heads will have corrosion no matter what in the coolant pa$$ages. So unless I am missing something how is corrosion a factor here. The valves are sealed from water by the valve cover gasket, and the valves are not aluminum, then why so worried about corrosion?

Tim D, cars run cast iron blocks with aluminum heads all the time no head gasket issue there. So again the question is how is so differnt from the set up on a car. I am very open to other ideas on why it wont work or why it will work. But I am leaning more towards it will work.

ok see your point there, just thought you ment in general.

The guy pulling the engine from the CC Mustang between the trees in the BKH Redneck Engine Hoist thread, has been running Edelbrock Perf RPM alum heads, not on his Mustang, but on his Checkmate Chevy for some 6-7 years now with no problem. He has alum Kodiak exhaust manifolds as well. I've had the Barr alum exhausts on my Mustang since 98, and they still look great. But wait a minute, this site has a handfull of Interceptor, Holman Moody, and Commander alum exhausts that have been out there for up to 40-plus years, bolted to iron heads, but I guess they don't get as hot as the heads.    

reid.. have you ever used a "doug herbert" cam, I know they are made in NC..

ps..do you have any extra tickets for the 500??