Headers Or High-Flow Cats+Customer Y-Pipe

[ConElite]

Well I live in Cailfornia where its that you cant run Long Tube Headers.

Option #1
So I would have to go with Mid's (if they dont relocate the Cats) or some shorties.

Option#2
On the other hand I heard that the stock Manifolds flow just about as good as shorties. Therefor I would say just get some High-Flow cats and Customer Y-Pipe.

Option #2 would cost a little more but I think would be a better option. What do you guys think Would be the best choice?

[MunsonGTA]

do you think you'll be able to pass the nazi smog test out there with high flow cats?

[DHolmes]

do you think you'll be able to pass the nazi smog test out there with high flow cats?

I passed in my lt1 with a hi flow cat

[Al 96 Ram Air T/A]

I live in NJ, which has the same issues you do in California. I decided to go with LT4 stainless manifolds. Only a handful were ever produced, and you'll be hard pressed to find them, but the stock manifolds can be made to flow "better" with simple porting. From what I've seen, the small performance gain from a set of uncoated shorties was not worth the issues (at least for me). Coated...well there are potential thermal gains, but again, not worth all of the trouble for me.

I don't think I'm leaving much on the table vs. going with shorties. With my bolt-ons, I put down 292 hp, 30x(?) ft/lbs to the wheels. I'm happy...

Now, if only I could get away with long tubes...

[ConElite]

Al 96 Ram Air T/A, You have an LT1. Im running an LS1. They are different. and for the work put into getting the headers off to just port, id rather change them than spend $100-300 to get the stockers porter (which i have never heard anyone do). Shorties do help. My brother got shorties on his 96 z and they made a diff. As for the High Flow cats, I can get away with them.

[RAF7789]

any high flow cat is illegal on any OBDII vehicle in California. that is the law, however you can get lucky.

[ConElite]

Are 96 Z's OBDII?

My brother has a Random Tech Y-pipe with cats and its 100% legal. From my understanding as long as it does not relocate the cats your good to go.

[Christopherrr]

When you go get your emissions done, what do they do?

In GA they connect to the OBD and run the test...as long as your OBD is ready and there isn't a SES light, you pass.

No visual inspection or anything...no sniffer, no dyno.

Do they do all of that in CA even with OBDII?

[ConElite]

oh yeah they do it all. On my honda I had to go to some that would Hook it up with the visual b/c the header or the intake didnt have carb#'s. Passed the Sniffer.

The T/A they just connected the OBDII and did a quick visual. Asked about the SLP Lid and I told him thats from the Dealer and he believed it. Then he looked under for the Cats then did the Sniffer on the rollers. One test at high speed and one at low speed. Then I believe the average it out and that tells you weather or not it passes.
Its horrible.

[Al 96 Ram Air T/A]

Al 96 Ram Air T/A, You have an LT1. Im running an LS1. They are different. and for the work put into getting the headers off to just port, id rather change them than spend $100-300 to get the stockers porter (which i have never heard anyone do). Shorties do help. My brother got shorties on his 96 z and they made a diff. As for the High Flow cats, I can get away with them.

Duh...didn't notice that. My bad...

[Christopherrr]

oh yeah they do it all. On my honda I had to go to some that would Hook it up with the visual b/c the header or the intake didnt have carb#'s. Passed the Sniffer.

The T/A they just connected the OBDII and did a quick visual. Asked about the SLP Lid and I told him thats from the Dealer and he believed it. Then he looked under for the Cats then did the Sniffer on the rollers. One test at high speed and one at low speed. Then I believe the average it out and that tells you weather or not it passes.
Its horrible.

Oh my goodness! Insane!

[Joe 1320]

If you look at the LS1 manifolds, you'll notice that they are far better in design that the previous LT1 manifolds.



The factory Y pipes need some help though as they get squashed somewhat as the driver's side downpipe crosses under the engine/transmission. you'll pick up an easy 10HP just in the Y pipe, the issue though will be whether or not the specific part is 50 state legal. The factory cat on the driver's side isn't too swift either, but that's another emissions legal issue. Technically, you cannot even replace the cats with higher flowing units unless you can prove that the factory unit was defective. I say technically, because certain states are buttheads when it comes to modifications. You also cannot relocate the cats to a different area either.