aluminum head advantages?

[wvnova]

i've got a 509 world products merlin steel heads. what advantages do alum heads offer? i know reduced weight. are they worth the extra money just for 85 lbs of weight? do i gain more power, if so how much?

[mrn2obelvedere]

85 lbs is a lot of weight. Furthermore, the weight is being taken from a relatively high spot on the car, lowering your CG. That is the main advantage. From what I have read, if you had an iron head identical in every way to an aluminum head, the iron head might make more power because it traps more heat in the combustion process. Also, (and maybe for the same reasons) the aluminum head dissipates heat more readily and is less prone to detonation.

[1969CamaroRS]

Usually you can run a full extra point of compression (10.5-11.0 to 1 compared to about 9.5:1 with iron) w/o detonation with aluminum heads compared to iron heads, which should be a fair amount of extra power. Really depends on the motor as to how much.

Along with lightweight and a bit cheaper/easier to machine or port as well as repair are all advantages of aluminum. Aluminum heads are also usually designed with performance in mind so they tend to have better flow numbers. Also Aluminum heads have better heat conductivity resulting in less chance of hot spots (which can lead to cracks). Also don't discount taking off 85 pounds in weight off the front end, that is huge!


Drawbacks other than the obvious extra cost, and you really need to pay attention to torque specs and make sure to use anti-seize on all bolts. And aluminum expands when hot a lot more meaning you need to run a specific head gasket and can mean needing to pay closer attention to valve lash specs.

[Edit]
As Sean said if the flow numbers and compression ratios where the same Iron will generate a bit more power due to keeping the heat in the combustion chamber but if you run 1 extra point of compression that more than makes up for this even ignoring and difference in flow numbers.

[Rod]

just dropping the 85 pounds from cast to aluminum is worth a few ponies in its self

[Pro Stock]

Usually you can run a full extra point of compression (10.5-11.0 to 1 compared to about 9.5:1 with iron) w/o detonation with aluminum heads compared to iron heads, which should be a fair amount of extra power. Really depends on the motor as to how much.

Along with lightweight and a bit cheaper/easier to machine or port as well as repair are all advantages of aluminum. Aluminum heads are also usually designed with performance in mind so they tend to have better flow numbers. Also Aluminum heads have better heat conductivity resulting in less chance of hot spots (which can lead to cracks). Also don't discount taking off 85 pounds in weight off the front end, that is huge!


Drawbacks other than the obvious extra cost, and you really need to pay attention to torque specs and make sure to use anti-seize on all bolts. And aluminum expands when hot a lot more meaning you need to run a specific head gasket and can mean needing to pay closer attention to valve lash specs.

[Edit]
As Sean said if the flow numbers and compression ratios where the same Iron will generate a bit more power due to keeping the heat in the combustion chamber but if you run 1 extra point of compression that more than makes up for this even ignoring and difference in flow numbers.

Ditto and X2, also aluminum is almost always repairable and 85 lbs in a typical drag car is worh about .08 hundreths of a second in e.t. which is a bunch and would really add up on a road course.

[wvnova]

thanks guys