Slowly but surely finding out the info I need, but it would help to know if anyone has bolted these alloy heads on in place of the originals, and what was the result - and was it done with other mods ???

 

Couldn't tell you how they work yet, but I've got them on my ZZ4 that I'm installing. From everything I've read, they're great heads. Good flow numbers, GREAT e/i ratio, and you can run at least 10:1 compression with them. You can definitely bolt them on to some stock cast iron blocks (such as the ZZ4 block). The d-shaped exhaust ports limit your choice of headers a little bit, but the rumor on the street is that GM found that round headers and d-shaped had the same performance value.

Dave

 

I heard all that too, but to the negative, I also had a set of Edel heads that allowed a cyl head gasket failure upon heating up to 250f.....iron don't do that...and so also my experiences with a stock L98 engine in my '87 vette with those heads and the leaking intake gaskets filling up the oil with water....

sorry folks, the scrub and temp variations of aluminun to iron on a V8 configuration are too much to be coped with for ultimate reliability....in a 4 cyl puddle jumper...fine....apparently...
but think about it with all that iron and aluminum fighting each other in a basically uncontrolled situation......significantly differant than a piston of X dia in a cyl of Y dia and variations therefore are controlled within parameters....

two aluminum 350v8 sets of heads, one factory, one Edel, and two gasket failures....one from never a heat problem from the factory on the intake manifold...and the other aftermarket with a head gasket failure.....

take your pick.....

case closed....

GENE

 

Yeah I have them. Pocket ported by the previous owner and bolted on to the original engine. When I got a new engine I kept the heads. So I have a performer RPM manifold, headers, double pumper carb, etc along with the heads.

The good thing about these heads is they are relatively cheap and easy to get, they come standard on the ZZ4 engine. Several chevy small block builders swear by these heads because they are good for low end street torque and because they are inexpensive. Among those are John Lingenfelter. They can easily support 350 HP, and with some port and polish work you can get 400HP+ out of them.

Now the negatives - they don't flow as well as other (aka more expensive) heads on the market, the valve size is 1.94/1.50. The port volume is 58cc which means you will bump up your compression. That's a good thing but with flat top pistons my compression is around 10.7/1. My pistons are forged, I wouldn't do that with cast pistons. Also as someone stated they take special headers and also special rocker (self-aligning) arms but I think chevy has a model that will fit.

I don't know anything about alum vs. iron leaks along the gasket, but it sounds like that would apply to any alum heads. You would think after market sales of alum heads would be in the toilet if that was a serious problem, but who knows.

 

Greetings,

I am also surprised about gasket problems, etc, because I was brought up with old Rover straight 6's and they gave no trouble, despite the head of a straight 6 being much longer than a V8 .........
And then theres the BMW range....
Regards,
Hugo

 

That's the chamber volume. The valves can be enlarged to 2.00 & 1,55 (milled down 2.02/1,6 valves)
There are 2 alu L98 heads, the ones to get are the D port heads with the little extra quench pad above the spark plug hole, they are cast # 10088113 or GMPP P/N 12556463

 

Very true. Mine were actually modified to 2.02 and 1.6. The ones to get (cast #10088113) came out in the 1988 model year and they have increased exhaust port flow.
Another plus for these goodies are the weight savings - 19 pounds vs. 44 for a cast iron head.

 

how did they get those valves in there? When you go to 2.00 and 1.55 the valve seats are " siamesed" against each other. I don't see how you can get larger valves in there without moving the seats and getting offset guides...lotsa work.

 

I have no idea, the previous owner who is also a previous forum member (I think he's still around somewhere) modified them and claimed that these were the valve sizes, maybe he was mistaken. I have also read that the maximum valve size is 2" and 1.6".