ZZ4 heads
Drifting
Joined: Feb 2002
Posts: 1,952
Likes: 2
From: Little Rock Arkansas
Re: ZZ4 heads (corvette0096)
You'll also need to slot the base manifold's bolt holes as the aluminum head's mounting holes are slightly higher; but, that's really the only diff.
-Jeb Burnett
-Jeb Burnett
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Re: ZZ4 heads (jburnett)
You'll also need to slot the base manifold's bolt holes as the aluminum head's mounting holes are slightly higher; but, that's really the only diff.
-Jeb Burnett
-Jeb Burnett
I was wondering how about the Vortec heads that so many guys ask about. I know that slotting the intake manifold bolt holes is needed to allow the manifold to boltup but does this effect the port alignment.
You outta see the problems we've been having trying to get a TPIS Miniram to bolt up to set of Brodix 15 degree heads. I mean NOTHING aligns, not intake port, water ports, bolt holes, and the end gaps are so big you can put your index finger in it.
Thanks,
Jake
Jake
Drifting
Joined: Feb 2002
Posts: 1,952
Likes: 2
From: Little Rock Arkansas
Re: ZZ4 heads (JAKE)
Umm...Yeah, I can imagine you're having a problem. A customer wanted to use a set of 15 degree Pro Action heads on his 434 with a MiniRam. I mocked everything up and told him that I was going to have to cut the flange off the runners, rework everything and then have my welder TIG it back together; it was gonna be expensive. Instead I got him a Pro Action single plane manifold and welded EFI bungs in it!! Much nicer, much easier, and MUCH CHEAPER!! The Vortecs are a totally different animal than the ZZ4's BTW. They have a completely different bolt angle than any other SBC head, they're verticle. You actually either have to buy a specific manifold for em (Scoggin is now selling a big-mouth TPI base for the Vortecs) or weld up the holes and re-drill... PITA!!! Really the only diff between the aluminum heads and the old 882's that were used on the early TPI's is the angle of the hole; a lot of aftermarket base manifolds already come with the elongated holes to fit both later aluminum heads and early (pre-86) applications.
-Jeb Burnett
PS- Good to see you here too, Jake!!
-Jeb Burnett
PS- Good to see you here too, Jake!!
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Re: ZZ4 heads (jburnett)
Yep, Jeb, that's what had to be done for a 434 I'm doing. Thankfully all this is way outside my area of expertise; Bob Jones' has had the headache with this mod.
That manifold has been cut open so many times and re-welded that it's a wonder it's still able to hang together.
First it was to port it to remove the turbulance that set in at just over 320 CFM; then it became a matter of improving the flow even more so that it didn't present a restriction to the heads, which flowed over 340.
Then came the angle problem with the bolt hole mismatch.
So the manifold got shipped to us from CA for me to mock up and the water ports weren't even close to covering the water ports in the heads, so back to CA they went.
Latest word is that all that's been fixed and the heads are due here anyday. The manifold is being held back for lots of photos and may be featured in one of the car mags.
What a nightmare, but at least all the bugs are out incase anyone needs those mods in the future.
Jake
That manifold has been cut open so many times and re-welded that it's a wonder it's still able to hang together.
First it was to port it to remove the turbulance that set in at just over 320 CFM; then it became a matter of improving the flow even more so that it didn't present a restriction to the heads, which flowed over 340.
Then came the angle problem with the bolt hole mismatch.
So the manifold got shipped to us from CA for me to mock up and the water ports weren't even close to covering the water ports in the heads, so back to CA they went.
Latest word is that all that's been fixed and the heads are due here anyday. The manifold is being held back for lots of photos and may be featured in one of the car mags.
What a nightmare, but at least all the bugs are out incase anyone needs those mods in the future.
Jake
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Burning Brakes
Joined: May 1999
Posts: 999
Likes: 1
From: Gardner KS
Cruise-In II Veteran
Re: ZZ4 heads (JAKE)
Didn't see this mentioned but the alum L98 heads never changed as far as intake bolt pattern goes. Only the iron head L98 motors (F-bdy) changed on the center intake bolts. An iron head Vette L98 intake will bolt right up to a ZZ4 (L98 alum) head. The EGR problem mentioned above becomes obvious when you realize the ZZ4 heads have no EGR ports. Just wanted to drop that in here. -Jeff
Instructor
Joined: Dec 2001
Posts: 247
Likes: 0
From: San Diego CA
Re: ZZ4 heads (corvette0096)
Thanks I was totally spacing there. I am glad at least someone has looked at my pictures at least!!! It seems like there is no interest in my car at all. Makes me wonder what is wrong..
