Recommend a better set of heads for a ZZ4
 

I'm not terribly impressed by the heads that come with this engine, so I'm looking for opinions from those of you who've swapped them for something else.

When considering recommendations for my setup, keep a few things in mind:
1) This will be a daily driver, so keep it realistic
2) The heads will be the only things changed out. (Rules out Vortecs).
No cam swap, etc.
3) I'd like to stay near 10:1 compression.

As always, TIA for all helpful replies

:cheers:

gmpp fasrburn theese heads have the potential for 500 hp and their made by the general they also have 62cc combustion chamber so it will not affect the compression as much as a 64cc, 72cc ,76cc head when it comes time to buy heads for my vette it either going to be fastburns or a.f.r. 195s

another option even though you said no cam change it would be a lot cheaper to keep those heads and change the cam to the gmpp lt1 h.o.t. cam set it come with every thing you need to make the swap for under five hundred dollars and can be done in a day and this set up is still very drivable and really wakes this motor up 12 second time slips would pretty easy with the right gears and traction i done this exact setup and the motor pulls hard

You should look at a 70 LT1 engine and use those components as it`s the last year of good HP parts for a Vette. Especially the heads...:thumbs:

thier the same heads that they put on the zz385 thier the only difference between the the two motors zz4/zz385!

I have a ZZ4 and felt the same way... I switched to AFR 195 Street Eliminator heads and had them angle milled to 58cc to maintain the 10:1 compression... I couldn't be happier. I did switch to a COMPCams Magnum 180 at the same time however... you should at least look at changing the stock 1.5 rocker ratio to 1.6 while your at it.

195 AFR's
 

A8skyhawk,

That sounds like a killer motor combo! I'd like to build something similar, as I'm running L98 heads on my 350 now and (like partTimeGenius) would like more power. Any dyno or track numbers with this combo yet?

I don't have any official dyno or track numbers for you. However, I do have Gtech PRO and DesktopDyno data.. which is supposed to be fairly close- Gtech more so....
DesktopDyno says im making 440 ft-lbs at 4500 RPM and 460 HP at 6500 RPM (I have the AFR Hydra Rev Kit to help me spin up that high- so far i've ony been there once with no signs of valve float) but it also says I'm making 448 HP at 5800 RPM which is a little more reasonable.
I've only made a few passes with the Gtech on a deserted straight stretch of road and have had ok results. Launching at 2000 RPM on street tires (a little bit smoky) with a 3:36 rear resulted in an average of 13.6 at 106 mph 1/4 mile. I plan on getting some stickier tires and going out to the strip this spring. I will surely let you know how it turns out.

Wrong O. The intake manifolds are different. The ZZ4 engine uses the #10185063 dual plane. The ZZ385 uses the #12366573 vortec dual plane.

The fast burn heads can be used with a standard bolt pattern intake that has raised runners. It will not match up with a standard single/dual plane manifold. It has to have the raised runner designation.

The AFR 195 Eliminators will be too big if your not swapping cams and such. I would sell the ZZ4 (Corvette) heads and get the AFR 180 Eliminators.

:iagree: I got around $750.00 on Ebay for my <4000 mile ZZ4 heads. Apparently there is a "stock" ZZ4 racing league out there somewhere that can't get enough of the ZZ4 parts... to include the original "replace upon removal" timing cover and bolts...

PartTimeGenius,
How fast are you looking to go in your daily driver?

I'll agree the stock ZZ4 heads are not all that impressive, but they can produce decent HP numbers. I'm running 12.8 @ 108 mph in the 1/4 mile with the following mods to the engine. Oh, and the car is setup more for road racing than drag racing ... these numbers were produced when I was running NITTO 450's, which are actually SUV tires.

1 - Lightly ported heads at home (using abrasive wheels cleaned up part, removed machining steps, etc. ..... not port matched to intake, or any agressive mods to the flow path).
2 - Replaced valves with Manley's Race FLow stainless valves (improves flow when valve is under 0.300" lift area) ... stock size, no valve job was done.
3 - AFR rev kit
4 - GM's Hot Cam w/ roller rockers

I am looking into AFR heads myself, so its not that I am a supper fan of the L98 head, just wondering what your goal is for your engine. You may not need more head unless you want low 12's.

you could just take the heads off the engine and take them to the machine shop. have them run the flow #'s and see whats going on, you may need some massaging and that will greatly increase your overall performance of the engine-maybe cheaper than new heads