I am going to swap out my 305 for a 350, and I am considering a crate ZZ4. The Vortec intake from SDPC also looks promising. My question is, has anybody put a Vortec intake on a ZZ4? I need to keep the EGR because of emisions. I know that I will have to drill the center bolt holes to bolt the intake to the heads, but is that all tht I will have to modify?
Thanks, Tom

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86 IROC T5
MSD 6A
Summit cam
Flowmaster
AFPR
Lowered 1.5"
My own prom

 

You're mis-mixing and mis-matching parts here.

The Vortec manifold is unique for the Vortec heads because the heads have different intake mounting bolt hole locations and relocated intake ports. The Vortec manifold will NOT fit ZZ4 heads, period.

The ZZ4 heads, however, use "normal" intake manifolds, like an Edelbrock Performer or Weiand Action + (or even your stock manifold). These are available in EGR models, but like you have probably figured out, the ZZ4 heads don't have the exhaust crossover passage that the factory used to feed the EGR valve.

The solution is to plumb exhaust gases from your exaust manifold or header up to the intake manifold passage. In their HO 350 Conversion Kit, GM did that via the extra hole & mounting boss on the ZZ4 intake manifold, used in the 70's for the hot air choke they had back in those days. If you get a ZZ4, you'll get that manifold, which is as good as or better than the Performer or Action +. As you can see in my sig, that's the manifold I'm using, even though I don't have a ZZ4 engine. If for some reason you don't end up with a ZZ4 intake manifold, the other choices can be modified to put a fitting onto the side of the intake crossover passage so a tube can be fastened to it.

By the way, Vortec heads don't have exhaust crossover passages, either.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4, 2300 stall TC. Ported World 305 heads, Crane PowerMax 2050 cam. ZZ3/4 intake, oil pump, pan & baffle. Accel HEI SuperCoil & module. Hooker 2055 headers, 3" Catco cat & 3" catback w/dual-opposite Flowmaster 80. 2.93 limited slip. Spohn SFCs waiting to be installed. AMSOIL syn lubes bumper-to-bumper. Daily year-round driver. Best ET, speed TBD...
57 Bel Air, my 1st car. '66 396, 9.7:1 forged TRWs, Weiand Action+, Holley 750VS w/4150 conversion, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 700 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

 

Thanks for the input. I know that the ZZ4 heads do not have the EGR passages in them that is why I thought I could use the Vortec TPI intake becuse of the provission in them for plumbing in the exhaust. What TPI intake could I use on a ZZ4 with external EGR?

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86 IROC T5
MSD 6A
Summit cam
Flowmaster
AFPR
Lowered 1.5"
My own prom

 

Corvette TPI base. Or aftermarket version. For the price, it would be better to get the vortec engnie and the new vortec base.


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-Tas
'89 Formula WS-6

305, TBI, 700R4, P.A.W. 14x3 open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips, Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248)
Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options

 

You didn't mention TPI in your original post. So, I chattered on about carb intakes. Oh, well.

I still like the ZZ4 over the 350HO. I'm no fan of Vortec heads for several reasons, limitations on intakes being one. Better parts in the ZZ4 that can handle future modifications and/or will last longer as-delivered is another.

A Vette-style base like the BigMouth is a good choice for the ZZ4. You'll need shorter/larger runners, plenum modifications, AFPR, and probably larger TB as well as PROM work. Bud of mine here has just such a combo (but a SD rather than MAF system) and passes emissions with ease.