I am still debating my next choice of heads for a reliable street motor. I lean towards iron heads at this point, because I think they are pretty much bolt on and forget. What issues would I face with an aluminum head big-block motor? I like the lighter weight and higher static compression rations possible with the aluminum heads, but worry about head gaskets and other aluminum head issues. What are the pros and cons for a performance street motor that is a daily driver?

Thanks,
Mike

I am still debating my next choice of heads for a reliable street motor. I lean towards iron heads at this point, because I think they are pretty much bolt on and forget. What issues would I face with an aluminum head big-block motor? I like the lighter weight and higher static compression rations possible with the aluminum heads, but worry about head gaskets and other aluminum head issues. What are the pros and cons for a performance street motor that is a daily driver?

Thanks,
Mike

I don't see any negatives with modern aluminum heads, unlike the early GM heads that had all kinds of ugly issues.

The castings are about 10 times better, guides are better the material is better everything is better. As long as you don't pick a head to big for your combo you will be super happy.

I use the GM aluminum fast burn head on the mouse that roars:)

No doubt, Wally is right. But, there is a guy in my area who has a four year old ZZ4 in his '66. He has had problems with the aluminum heads eroding. A local machine shop fixed the problem by building up the eroded area with an aluminum weld and milling it. The problem surfaced again in another area. I don't know if this problem has been solved with more recent castings.

No doubt, Wally is right. But, there is a guy in my area who has a four year old ZZ4 in his '66. He has had problems with the aluminum heads eroding. A local machine shop fixed the problem by building up the eroded area with an aluminum weld and milling it. The problem surfaced again in another area. I don't know if this problem has been solved with more recent castings.

Smells like electricity at work, kind of like what happens on boat outdrives that set in the water around other boats.

I wonder how the motor is grounded, bat cable to the alt. bracket or directly to the block or frame???

Interesting...

Wally are you implying that the ground should not be on, nor pass through, an aluminum head?

Interesting...

Wally are you implying that the ground should not be on, nor pass through, an aluminum head?

No but it is possible for the ground to be marginal. The best ground is the frame, block tied to the frame, body tied to the frame etc.

It could be something like Electrolusis (sp). Two dissimilar metals in the presence of an acid make small electrical charge. I would research to see what type of coolant he is running, if he has hard water in that area etc. He could try dropping a couple zinc tabs in the radiator and see if that helps.

they make zinc tabs that hang from the red cap..
go to a boat place...
they'll have um..
all new cars could use um..

on the head thing
race gas/ pump

all things being equal iron will make more power
but finding heads with the same port etc as alum. one isn't easy..

all things being equal iron will make more power


myth, there was an article in carcraft comparing iron-aluminum down to a T, the heads were identical minus their material, the aluminum made a few more ponies actually, they said probably due to running a bit cooler. They tested them with the engine "cool" and the engine "hot" with both heads, theres no way to spin it/debunk it, all things being equal the only choice you need to make is do you want to save the 50+ lbs on the front of your motor?

Thanks to all for the responses. I still can't make up my mind. I guess I'll waffle until the last minute....