Psychotron

What are the advantages of aluminum heads? I know they changed in mid-86, so did ALL '87 & up C4's have aluminum heads? In your opinion, is it important enough to base the purchase of a car on, or is it something that is cheaply changed if desired? i.e. if I decided later on to do a cam/intake swap...
Thanks.

scorp508

When the mid-86 occurred, all Corvettes from that date on to this day have had aluminum heads. They are MUCH lighter, and dispense of heat much better than the iron heads did. They are probably much easier to work with for porting, but i have no experience in that area.

Both of my cylinder heads full assembled weighed less than one iron cylinder head off of my brother's 1990 V6 W/T 1500 Chevy truck.

01GT

Chevrolet actually started putting the heads on in early 86 and had some
recalls,so they fixed the problem and they went back on in mid to late 86.
They are roughly 40lbs lighter than the iron heads.
01GT :cheers:

Dr. Evil

A big advantage is heat transfer or disipation as well as the weight savings. You can generally run a bit more timing and compression with alum heads vs iron.

dgoodhue

44lbs according to the 86 Press Kit :)

65Z01

In addition to the lighter weight the Al heads were rated at 5hp more than the iron; the later D-ported Al heads brought another 10hp gain.

If I were considering the engine I would look for a roller cam. The heads are relatively painless to change but going from a flat tappet to a roller is a bit more of a deal.

vader86

several advantages-less weight, more compression, get rid of the engine heat better, easier to port them

all this equals the magic words=more HP :D

01GT

dgoodhue,
I stand corrected!The heads are 44lbs lighter.I said about 40lbs.
Are we **** today or what?
01GT :cheers:

HighHopes85

Aluminum is the way to go, but if you are budget minded then you may look at iron. If you had identical heads, both the same casting and one was iron and the other Al, the iron one would produce more HP. It is because of it's heat retention.

But you have all the drawbacks mentioned above.

cire96

While aluminum heads do weigh less, are easier to port, the primary reason they are used is because they transfer the combustion chamber's heat more quickly, thus allowing more agressive timing and higher compression ratios. All the rest happen to be side benifits. As a result, an aluminum head will allow better performance. Cire96

Psychotron

So in other words, if you did a cam/intake swap and already had aluminum heads, you would get more benefit from the swap than if you had cast iron heads (i.e. the alum heads take better advantage of the cam/intake improvements), right?
How much is the average cast iron to alum head swap? (stock alum vs aftermarket)
Do most people doing this kind of swap just go w/aftermarket alum heads rather than factory alum?

vader86

AL heads would take better advantage of the swap because they would allow more compression and timing, so you would get a little more hp out of them.

Although, as said above, if you buy the right brand of Iron heads, (Dart Iron Eagle makes pretty damn good ones) you could get the same numbers out of them. However, the weight savings are where to go so get aluminum.

Factory Aluminum heads were pretty good in the late 80's and throughout the 90's. The 89 heads were called D ports and ported will support 350-400hp, and the LT1's heads were even better. We go aftermarket, usually AFR 190-195 heads, because they flow even more than the factory heads. (LT1 heads dont fit on L98s)

I would check out AFR's website for pricing, or order yourself a Summit or Scoggin Dickey catalog and look around for the best prices. (anything for Small Block Chevy will work fine, unless its specifically made for the LT's or LS1) http://www.airflowresearch.com

scorp508

1988 was the first year of the D-port heads. Untouched they can support 350hp.