Julie Bergman

I would like to buy me a set of SLP 1-5/8 headers for my '91 Formula WS6 with 305 and T-5. I have located a barely used set, price is good, coolness, except the y-pipe is for a single cat car. In California both the headers and y-pipe need to be EO pieces so I cannot modify that single cat y-pipe. Does another EO y-pipe like the Hooker bolt up to these headers? Unfortunately the SLP dual cat y-pipe is no longer made and I have not been able to locate one.

Julie Bergman

Ok, let me try this angle of this question: Does the Hooker emissions legal y-pipe for a dual cat 91 Formula work with SLP 1-5/8" headers?

Thanks ahead of time!

91Z28-350

Hey Jules, no, don't think so.

Hedman 68491 is the only one still made, IIRC.

Julie Bergman

Interesting Kev, guess I will have to keep hanging out on e-bay...I bid on a SLP dual cat y-pipe on there and it ended up going for $510.00!!! Needless to say, I was not the wining bidder!

Would it be better to just get the SLP 1-5/8 headers and just go with the stock y-pipe? Since my scenario is so dang limited!

91Z28-350

This isn't Kev.

The stock y-pipe won't connect to headers unless you cut them, shift them a bit and put a flange on it.

Tri-Y's come up on e-bay now and then too.

Or you can go for Hedman 68491. A new set should be around $500 or so coated. About $300 or so uncoated. They aren't the best set of headers, but if your engine is going to be mostly stock, it'll do just fine.

You probably could cut the SLP Y-pipe for the single cat and move things around and add some extensions and get them to fit. I know it's technically not legal, but, most smog techs won't know the difference, and most don't check. They just check for cats. You could also have Alan make you a set on his mandrel bender. I'd really doubt they'd know after that. He can probably duplicate the SLP dual cat y-pipe.

Julie Bergman

Realized that after I had sent off the reply.

Tell me about the SLP Tri ys. Any big difference performance-wise between that and their present header?

91Z28-350

They are supposed to be better than the 4 to 1 shorties, but I've never had a set and can't really comment on it from experience. All the ones on e-bay seem to go for a premium.

The dual cat cars have very limited options for headers now that SLP discontinued theirs.

Julie Bergman

That's just like SLP to not selll what the people want!

zNucleaRz

They were offered through SLP but discontinued. Hooker does offer a dual cat setup part number should be 2056 but must be ordered through Hooker. Hope this helps.

five7kid

iTrader: (14)

I haven't heard that Hooker would even fill a 2056 order, but I haven't heard of anyone that tried and failed, either.

Edelbrock and Hedman both make emissions-legal dual cat header sets. Go in the $350 range from Summit.

anondude13

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Julie Bergman

Being CA you cannot do anything that is not 50-state EO approved before the cats. It is cat back (after the cats) that is "free." The previous owner put on a Flowmaster catback, sounds nice!

I will giving SLP call about the y-pipe! Thanks for that info!

anondude13

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five7kid

iTrader: (14)

In all honesty, I don't know why you couldn't have a y-pipe fabricated that mimics the SLP pipe. They're going to be looking at the headers and cats, not the pipes in between them.

rocluvr0013

No tech is going to know or care if the piping itself is not actually an slp piece. Just have one mandrel bent to mimic the slp peice like was stated earlier. Just so long as there are cats and it passes the sniffer.

VincentZ28

iTrader: (2)

You can buy a flowmaster y-pipe 2 2 1/2 into 3 for about 30 bucks and have a muffler shop that is willing to build a dual cat system. It will be cheaper or better than stock. thats what I did for my 86 Z28 with SLP 1 3/4 headers into dual 2 1/2in pipes(stock SLP 2 1/4 pipe) into 3in pipe to the Hooker Maxiflow 3in muffler.

RPOL98

I have the SLP 1-3/4" dual cat headers. I bought a Flowmaster cat-back system, it came with a Y-pipe which worked fine, really nice piece. I replaced the cats with straight pipe, which met up with the SLP pipes. I recall seeing the Flowmaster IROC Y-pipe listed separately, so you could purchase that separately. The exhaust system replacement (SLP headers, no-cats, Flowmaster cat-back) really improved the character of the car, took it to the track, and it just smoked the drag-radials through 1st and 2nd, kinda ridiculous, didn't do that before. Now, I need wider, better drag radials.