Factory semi dual exhaut

[Tavi]

Ok. I'm about to move back to California. I have a 92 K3500. I need to stay smog legal. I know the 95? and later HDs models have dual cats, and exhaust up until the muffler. Which I've read GM did an amazing job of designing. To stay legal would I be better off buying a replacement factory setup for the later model. Or just fabbing up a new one. I know I can only have a single exit. But I'm not to worried about that. The crimped bends and small single diameter in front of the can is what really bothers me.

I'm also looking for some 50 state legal headers for the big block. Inexpensive please. But not cheap.

The goal is MPG(yes I know its not a prius). But at the rate she drinks gas. even 0.5 increase is going to help the wallet. And a little more power.

I also plan a cam upgrade. And a little head work. Trying to get the compression up a little.

 

[Tavi]

Really? Nothing?

 

[slippy3002]

Don't move to California...you mean you cant buy a 50 state legal after market exhaust? How do car builders do it out there?

Sent from Robland

 

[slippy3002]

Summit brand shorty headers. They are cheap and made by pacesetter

Sent from Robland

 

[Tavi]

Been years since I lived in Cali. And this is the first vehicle that I plan to modify. That has to have a smog check. I was hoping someone could give me some insight on the subject. I'm currently stationed in Louisiana. Using the truck to move all my belongings. To include a few cars. Across the country. Making a stop in NM for a few months, to maybe a few years. But ultimately I'm going to end up in Cali. Where i will Have to smog it.

But the summits are 50 states?

Not seeing Summits for the BB

 

[slippy3002]

I was thinking for the small block. I'm sure there is a catback system that is 50 state legal though.

Sent from Robland

 

[Blind]

You can do whatever you want, so long as it is CARB legal.

On my 96, I have Gibson shorty headers, Magnaflow CA catted midpipe, and Magnaflow catback, all stainless and dual up to the muffler. This kind of setup would work on your `92 and pass the sniffer.
The biggest thing you will run into, is on visual smog inspection the tech will catch if they are familiar with your truck not having factory dual exhaust - it is illegal to alter the amount, or placement of the cats. But if that is a problem, I would suggest just trying another smog shop until you find one that doesn't notice/care.

For anything you want to get, look for a CARB exemption #, without this # on a sticker under the hood, you will fail the smog visual test, this counts for 'cold air intakes', throttle bodies, or anything that doesn't look stock when you pop the hood.

Catback doesn't matter, you can do whatever you want after the cats, but headers and cats have to be CA models. The cats on my magnaflow midpipe for example even have CA stamped on them in large letters.

 

[Tavi]

I'm aware of the CARB #s. But that is pretty much what I was expecting. Although I was unaware laws on altering number and placement of cats. So that was exactly the information I was looking for. I figured Cali had stupid laws like that. As far as passing visual. That's the main reason for going with a factory set up. So I wouldn't be lying when I said "its stock". Just don't need to tell them for that year.

Are the throttle body spacers worth anything on the TBI?

I know i can get away with any cam, as long as it isn't "noticeable." I've been told the smog allowed on the BBs is pretty huge. So its hard to fail the sniffer. The hard part is visual.

 

[Blind]

yep, you'll have trouble buying used though, any pick-n-pull type yards are not allowed to sell used cats, you can buy the manifolds/headers and catbacks, but the midpipes are all destroyed with pipe cutters that pinch the pipes in a few spots and they cut out/recycle all of the cats, really stupid law as I've come across brand new looking cats/midpipes on mustangs and trucks in the yards and they've been destroyed.

Even if the cam is noticeable the smog tech will usually not care, my `89 mustang has a trickflow cam and has a really hard time during the 15mph test staying running because it's bogging the whole time if the tech uses 2nd gear, every place I've had it tested I just tell them to use 1st gear for 15mph run and they're fine with it.

 

[Tavi]

Yeah. The used cat laws are stupid. I've heard a few storys of them being sold as precious metal from yards. I've found some new mid pipes on rockauto. Bout 800 for the whole thing. Ouch.

Good to know about the cam. I'm not sure how noticeable it will be anyways, since I'm going for torque. What about chips? How legal? Or can/will they even check.

Going for Cali legal, max torque, and hopefully a little help in the MPG.