91L98Z28

I'm interested in replacing the stock cats and Y pipe on my 91Z 5.7L (twin-cat equipped).

Anyone know of any suppliers of these parts? I've already got a cat back exhaust system, and I'm not interested in headers at this time, so I just need to get some fresh cats and a good Y pipe on the car.

Suggestions/comments?

Thanks!!!

91B2L

Best prices I've found is www.discountconverter.com the part # is 4153 for dual cats.$368 I think that's with shipping. I didn't pay over$380 for them. there made by catco. you could also take that part number and try local shops ie: autozone, pepboys,discount auto.

91L98Z28

Does anyone know of a nice aftermarket Y pipe that bolts to the stock manifolds?

I'd love to have a 2.25" or 2.5" mandrel bent Y pipe, run it through a pair of random tech converters, and then the merge into a 3" "collector" to the cat-back i already have....

91L98Z28

Ok, So i found the SLP Y-pipes....cool...

But I have a twin cat car and those appear to be set up for single cat cars.

Does anyone have knowledge of whether or not a pair of 2.25" converters will flow better than a single 3"?

Or if california law is going to frown on me for taking two cats off and putting one cat back?

91L98Z28

Ok, well, for anyone who it helps:

I called random technologies today.

They told me it's better to go with the dual 2.25" converters instead of one 3".

He (their tech guy) said that the 3" converter should flow around ~ 500 cfm, and that the 2.25" converters should flow around 300cfm. So the pair of 2.25" flow around 600cfm total. advantage to the twin 2.25" converters.

GKK

By California law, you can only remove or replace emmisions equipment if the vehicle is 5 years old or has over 50000 miles on it or if the equipment is damaged or not working properly. Also, whatever emmisions equipment originally came on the car has to be in place and in the same configuration. You can replace exhaust components with aftermarket parts AFTER the catalytic converters. You cannot remove or modify anything in FRONT of the catalytic converters unless (like some headers) the parts have a C.A.R.B (California Air Resource Board) certification.

1992B4C1LE

I live in the middle of the country so smog requirements are not even an issue. Definitely a plus with my old Camaro. Otherwise I suggest not using the replacement cats from Auto Zone. I got just some stock replacements and had a welding shop cut out the olds and put these in at 107k. 23k later I'm having the same problem. Not sure what the problem is but I'm trying to get Auto Zone to just give me a partial refund. Doubt they'll do it but worth a shot.

I want to keep the cats and all the stock look though since I like to show my B4C police package as stock but want to squeeze the ponies out of the 305 for some fun on the road. I'm looking at Random Technologies also. Checked out their web site today. Any other high flow options?