alright i was overhauling my stock heads last night on my 95 Z and noticed that my magnet didn't stick to the heads. i thought that was odd so i tried it with an older 350 that i know has iron heads and it stuck.

does that mean i have aluminum heads? i was under the impression only 4 bolt main engines came with aluminum heads. what's the deal?

 

The Corvette,Camaro & Firebird LT1's all came with aluminum heads. Caprice, Roadmaster, Impala SS & Fleetwoods got the iron heads...

 

And those lowly iron head flow more than the 95 aluminums , for 96-7 the aluminums caught up to the irons flow. And no aluminum is NOT magically better it desapaites heat faster taking it out of the chamber where it could have been used to drive the piston, but is instead wasted into the cooling system. It is that thermal disadvantage though that leads to the ability to use more compression offsetting the power loss from the heat escape. Not trying to say the aluminums are bad they do weigh something like 47lbs less for the PAIR and come with screwin studs so they do have advantages just really HATE the aluminum worship so very many gearheads suffer and feel compelled to dispell the myth it is inherantly better.

 

Really, you can't look at em and tell they're aluminum?

 

most of the engines i deal with are covered in grease and hauled out of junkyards. i don't pay close attention to what material things are made of. these heads are the first i've ever dealt with that i can actually see bare metal.

 

I have a set of iron LT1 heads in my garage if anyone wants them

 

So you are saying its better to have stock iron heads worked over than the stock aluminum ones?

 

Who would want those pigs?!

 

not me, I like my aluminum CHS heads alot better


maybe the impala/caprice guys might be interested

 

Not at all just saying the iron hated most gearheads feel is based on IGNORANCE rather than fact. I have a spare set of irons I was going to port because the car was to stay a mild daily driver, things changed and I now have a LT1 Roadmaster wagon for that purpose and the Caprice is slated to become a bit more aggressive, the porter I want to work with prefers the aluminum so I am looking for a set for myself.

Another advantage of the irons though is head gasket problems are nearly unheard of and overheating doesn't seem to hurt them, they would be a reasonable consideration for boosted applications.

 

You don't convert people to catholicism in your spare time do ya Dwayne?

Stock flow iron vs aluminum.... who really cares? If you never plan to have the heads ported or bump the compression then just stay with iron. Otherwise I'd step up to aluminum.

My 2 centavos.

-Mindgame

 

Don't fear the cast iron

 

porting cast iron sucks.

 

Thats why I use them. 40 lbs on a street car is not really a big deal, changing head gaskets is a big deal.

 

with 17 head bolts per bank you are doing something really wrong if you are blowing HGs with aluminum heads. ive run 18lbs of boost on a ford 302 (10 head bolts per bank) with gt40 aluminums (not the thickest decks in the world) making 550rwhp and never had a problem. so i dont know what you guys are doing.