Double Aught

I know Chevy says they are not made for smog-controlled vehicles, but has anyone built one that has passed a smog inspection? I would figure if you used smog-legal heads and carb, it would stand a good chance to pass. I have been kicking around the ZZ4 or something similiar to put in my Pace Car instead of rebuilding the original motor.

a smith

We put a ZZ4 In my friends 1977 with a Holly 670CFM Avenger carb.She passed the sniffer test just a little on the rich side on the idle test.

DREGSZ

It's easy to pass smog, it just depends how much you are willing to pay the guy.

63Banshee

The one in my GMC truck passes with flying colors.

Golden80

I'm planning on running my smog equipment (smog pump, comp controlled QJet, hi-flow cat, and smog headers) when I get my ZZ4. I'm pretty sure it should pass. If not I'm going to try and do a TPI setup on the ZZ4.

Matt

Gator81

My Summit crate motor (installed with all the original smog equipment) passes just fine. Essentially, I just replaced the long block of my L81 with the crate motor longblock. Everything else is the same, except that I removed the EFE flapper from the p.side exhaust manifold. All else is still there: EGR, PCV, computer controlled carb, air pump, air injected exhaust manifolds, stock exhaust with cat. The car passes the IM240 exhaust gas test with ease.

In fact, when I was trying to decide what to do about the motor, I really wanted a 406. But I was afraid the 406 might not pass the test, so I settled for a 355. Now that I see how clean it runs, I realize that a 406 with the same compression, cam, etc., would pass the test just fine, too. :(

The Summit crate motor has Trick Flow Twisted Wedge heads with about 9.2:1 compression, KB D-Dish h.e. pistons, a Crane Compu-Cam (duration at .050" lift is 210i, 216e; lift is .440"i, .454"e), Performer EGR intake, Accel upgraded ignition, bone stock E4ME Q-jet carb, 180-degree thermostat, and Hypertech Thermomaster computer chip. Every piece has a California emissions exemption number, so the whole deal not only passes the test, but is technically legal in all 50 states. It pulled 330 hp @ 5000 rpm and 390 lbs/ft of torque at 3500 rpm on Summit's dyno. As actually installed in my car with the stock exhaust, I would guess it makes 300 horsepower. The torque curve is quite high and flat, so it's very fun to drive.

With a cat in the exhaust, and an aftermarket chip (if the car is computerized, i.e., '81 and later) I would think a ZZ4 would still pass a smog test just fine. The ZZ4 cam is somewhat hotter than my Crane Compu-cam, so it will be a little dirtier at idle, but the cat should be able to handle that OK.
:seeya

joshc

My ZZ4 just got sniffed in Arizona, and failed the first time. Leaned out the edelbrock 750 carb and adjusted the timing (slightly) and went through the second time. Blew almost zeros, and passed with flying colors. The general concensus is that it is brand new and should blow very clean with the appropriate adjustments. Funny part is once you get sniffed, drive home, readjust for fun, and the whole thing was to generate revenue ( and keep the environment clean of course) Do it, you'll love the ZZ4. :chevy

Bob Turner

I think the main problem in CA is passing the visual inspection......... :mad

Bob :flag

Double Aught

It would have all the original smog equipment on. Small blocks all look the same with smog crap on them. I am going to crunch some numbers in the coming weeks and make a final decision next month. Thanks for the input guys.

BSeery

Ask me in 2 days. I am taking the new ZZ4 in for inspection.

But I am putting all of the stock AIR, EGR, QJet an other parts on for my visit.

Then they go back in a box for another year !!

Double Aught

I will do that. Also, I want to discuss the exhaust system again. We talked briefly a while back on upgrading to an 80 style factory exhaust.