I was researching some data and came upon this article:

http://www.carcraft.com/techarticles...est/index.html

I found it interesting they found no real difference between Iron and Aluminum heads.

As I'm working on another build (400 bored .060 over), I'm considering different heads. Recently, RHS heads have peaked my interest. The flow numbers on the 220cc head seem pretty decent considering the price point.

So comes the question. Since RHS offers the same casting in Iron and Aluminum, with the same chamber design and size, and the same flow numbers do we go with Aluminum or Iron.

The benefits have always been noted:

Aluminum takes heat out, so you can run more advance
Aluminum takes heat out, so you can run a higher DCR
Aluminum takes heat out, so it looses power over Iron
Aluminum is lighter

Iron heads don't strip threads as easy as aluminum
Iron heads have better (taper) spark plugs
Iron heads make more power because less thermal loss


Considering some of the results from the article in my above link, one could assume a lot of these facts are more like theories we have all believed (because the physics sounds right).

So I start to wonder, is Iron a more reliable candidate that makes the same power, at a cheaper cost with the only drawback being weight? (about 40lbs more total).


I've always been impressed with AFR heads, but honestly, I'm looking at RHS recently.

http://www.summitracing.com/parts/CCA-12322-01/

At $918 per pair, and decent flow numbers (265/186 at .500 lift) they seem
like a decent deal and outflow trickflow 195s. (252/183 at .500 lift)

http://www.summitracing.com/parts/CCA-12029-01/

Aluminum version at $1200 / pair.


For comparison sake, TFS 23* is $1,150 from summit

AFR 195, is $1,464.


While a $265 savings doesn't sound that great considering the flow difference between the RHS and the AFR 195, if you ponder the iron head making the same power (as the aluminum version) the savings is closer to $550.

When modeling in software, the difference seems to impact Torque by about 6 foot lbs..


-- Joe

 

i've always liked iron heads. The only big advantage is the weight difference. My motown heads flow 320 at .700 lift with a 2.080 valve. If you have the money for AFR's, then definitly go with them. I built 2 motors last month that both got AFR's on them. They run very well.

 

I was in the same boat. I was looking for some bare heads that flowed well out the box and were low in price for a 383 I'm building. I went with the RHS Iron 200cc head for $560 a pair bare cause it's a good head to start with and I do my own porting.
I don't like to run my motors with box stock heads anyway so going with the ported rhs will give me enough head to support 630+hp for less than $950. I don't care about the extra 40 lbs and I've done alum heads before and didn't see any diff in power output just price.