I am looking at 350 engines, the ZZ4 in particular. Of all the webpages that I look at, they say that they are used for off-road use only. Why do they say this? Here in GA, we have the sniffer test and whatnot. Would a ZZ4 be able to pass emmissions? From what I read from all the posts here, the ZZ4 is basically a bolt-in? It's compatible with the automatic and is an easy swap. I am in the extremely early stages of this swap. I'm just trying to get everything planned out then prepare for the swap. Any info or a pointer to an article would be deeply appreciated. P.S. For those of you with the ZZ4, how much did it cost you at the end? Sorry if that is a nosey question, just curious. ------------------ 1989 IROC-Z Convertible 305 TPI automatic White with black top Mods: K&N Filter Modded air box My webpage: http://mindspring.com/~humvee

actually, gm performance parts sells a lg4 to zz4 conversion, thats emissions legal... of course, its not tpi... but if all you have to do is pass a sniffer test... it should work...

Hmmm... stupid question, but would the TPI be able to bolt onto the GM ZZ4? I'm definatly not a carb guy. I have no clue about them. I'm just looking for 300 HP and the potential to go to 400 HP NA.

I know the TPI will restrict the ZZ4, but I'll use it to tide me over til I get the proper intake for it.

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1989 IROC-Z Convertible
305 TPI automatic
White with black top
Mods:
K&N Filter
Modded air box
My webpage: http://mindspring.com/~humvee

im not sure if the zz4 uses the 87' and up bolt pattern, i think it does though... if so the tpi would bolt right up...

Ah! Sweetness! How much HP do you suppose it'll put out with the TPI and the 'hot-cam' that they advertise? What type of intake would you suggest for the ZZ4? Mini-ram or something like that? Thanks for you help! Keep them coming!

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1989 IROC-Z Convertible
305 TPI automatic
White with black top
Mods:
K&N Filter
Modded air box
My webpage: http://mindspring.com/~humvee

i dont know... ive never owned a tpi car... id say maybe 360hp?!? i honestly have no idea... im sure a miniram would get you well over 400hp...

the guy that owns the local machine shop here in town once told me that hes ran zz4 on his dyno before and only got 340hp with headers and msd ignition... he says theyre overrated... over course he sells crate 350's too so he might be a little biased...

i think the website is www.pnx.com/procells

he advertises in chevy high performance magazine...

i think he sells a 390hp 2 bolt 355 with dart heads for right at $3000.

Oooh... I looked at those 350 that that guy sells. They put out just as much power as a ZZ4 and they are cheaper. Now, I'm not sure excatly which engine do I want to put in my car... I'm being tempted by all this power.



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1989 IROC-Z Convertible
305 TPI automatic
White with black top
Mods:
K&N Filter
Modded air box
My webpage: http://mindspring.com/~humvee

Well, lets open this discussion a little more. What engine do you suggest? I'm seeking relibility and 300+ HP or the potential to run high 12's or 13's with the TPI setup.
I've looked a little further and now I'm seeing these cheap 350 engines.

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1989 IROC-Z Convertible
305 TPI automatic
White with black top
Mods:
K&N Filter
Modded air box
My webpage: http://mindspring.com/~humvee

id suggest the 390hp 355... you cant beat that for $3000... ive talked to the guy before and taken a tour of the machine shop... and he knows his stuff...

of course, i dont think your tpi is gonna bolt up to those dart heads with out a little work... shouldnt be hard to do though...

but the 390 355 would be good on the street... 9.1 to 1 compression ratio...

One question...is there ANY way to make the 420 HP version emissions legal? Would crossover passages in the heads do it? Or should I just look for a nice wussy 305, 170 HPer to pass the sniffer? Also, forgive my stupidity, but how do you guys know it's a 355? I'm sure it's in the stats, I'm just dumb. Thanks.

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'89 RS LO3- 140,000 miles
14x3 K&N Open Element
Ram stock replacement clutch
Edelbrock TES (Jet-hot coated)
Catco cat
Edelbrock 3" Cat-back
KYB GR-2 Struts and Shocks
B&M Ripper
Pioneer DEH-P77
Midland 77-115 with 3' Firestik and 100 watt police PA
Dual .50 caliber machine guns just under ground effects

Coming:
Edelbrock Strut Tower Brace
Spohn subframe connectors

When your buddy reaches for a 10-pound sledge and says "I think we're gonna have to modify the floor pan, okay?" the answer is NO.

The ZZ4 is not overrated with the correct tuning in a carb setup I have seen REARWHEEL dyno numbers over the factory rating of 355hp. I have one so I am a bit biased but it is a strong motor that is well worth the money, to find a motor with 4 bolt mains and a forged crank and all new parts for less is hard to do. It is easy to pass a sniffer test the only issue with emissions is the EGR valve I left mine on the manifold and turned it off in the PROM. Also keep in mind that the ZZ4 or any other motor will give less HP with a stock TPI than with a carb but will make more TQ. After market high flow TPI will make good HP and TQ.

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1991 Z28 ZZ4 with LPE superram base, SLP runners, LPE 58mm T-body,Random Technology ramair,TES headers,24#svo injectors,ZEX nitrous,Walbro 255lph f-pump,Accel AFPR,Random Technology catback,!cats,and mutch more.

Also the ZZ4 uses the older intake bolt pattern so you would need to drill your intake base but I would not bother just get a Edelbrock or Accel base or Miniram or Superram they are drilled for both bolt patterns.

You would prolly also need a new prom burned for the new engine. It's flow characteristics and such are going to be WAY better than the stock motor..........

i also am looking at a crate motor for my 1986 trans am i'm hearing that these engines are no good for t-roofs and conv .my current engine is a305 tpi i would like to put a zz4 in it but everyones telling me i have to change my rearend and transmission i have the the 9 bolt with 2'77 posi so could someone give me some advice what to do and what engine should go good in my car

thanks

Some of those motors at PNX have high compression thats not good

It is possible. Fellow 3rd gen'r here has a '90 RS he's converted to TPI using a ZZ3 (basically the same as a ZZ4) as the base.

What he's done:
ZZ9 cam w/1.6 roller rockers; CNC porting of the heads; decked and shaved heads; Bigmouth intake, runners - all extrude-honed with the heads; ported plenum; 52mm TB; home-made AFPR; exhaust tube up to the intake for EGR; dual cats & 3" cat-back; SD TPI w/custom chip. He PUt 19 lb injectors in for the emissions test (dyno-type). He passed with "fast pass", basicaly meaning the initial levels were low enough to not require the full test.

He did most of this stuff for more power. The 19 lb injectors replaced 24 lb'rs - his times are better with the 19's.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. Cat-back from '91 GTA, ZZ3 intake, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/'87 LB9 block, ZZ3 cam, ported World 305 heads, Hooker headers & y-pipe, 3" Catco cat & 3" cat-back, Spohn SFCs).
57 Bel Air, my 1st car. '66 396, 9.7 CR forged TRWs, Weiand Action+, Edelbrock 1901 Q-Jet (Holley 3310 on the way), 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 @ 600 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

[This message has been edited by five7kid (edited August 28, 2001).]

So a ZZ4 will pass sniffer emmissions with a properly tuned carb then? What size carb - i was thinking a holley 750 w/ vaccum secondaries. Would a better than stock fuel pump be required with this setup? What about gas mileage? How bad is it? Thanks in advance
matt

I'd say your chances of passing sniffer would be much improved with computer controlled induction. Open loop mechanical systems just don't run as clean, although some "tricks" can be applied to get past the testing. Just don't try to drive it set up to pass.

I have an engine similar to the ZZ4 setup... it actually has a larger cam, more compression, and I ported the heads. Theres no AIR pump, no EGR, just a cat, and it passes emissions out here in the Republik of California no problem whatsoever, it actually met standards for a 99 car.

If you cant pass with the ZZ4, something is terribly wrong.

Just make sure your engine is running strong and correct, lean out your carb a tad, and you'll pass no problem.

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Chuck Kulchar
1991 RS
Open Element w/K&N
3" cat and Force II cat-back