I found this off of Moregrips post......

 

Almost looks to good to be true. What is that max diameter around the cat part, 4"?

I'm thinking of adding these to my Camaro SS, the exhaust smell is really getting to me...

 

4" is correct.

Here is some more info:
http://www.magnaflow.com/richard/NEW...LIC%20CATS.pdf

 

I don't know if I missed something, where did you get'em?

 

It appears the Magnaflow cat is the flow winner with the caveat that (I think) they are still CARB pending. The optimist says they flow 600cfm of 1000 while the pessimist says they block 400cfm of 1000. I still wonder, what about two cats at 750, 1000, and 1500 cfms and would they still pass smog?

 

summitracing

 

I can't find them on summit using the info oxidizer gave. Part #59926....

 

I can only find 59956 - 2.50", 59959 - 3.00" on summit.

This store on ebay has a bunch.
non sponsor link

 

Well....exhaust flow equation says you need 2.2 cfm per hp. So, 1200cfm(dual cats is what most will run) divide by 2.2cfm is ~545 hp where you will have no restriction at all. Anything above that....you could just put cutouts in front of that and that solves that equations problem.

 

Actually, I have 2 sets of cats with collector flanges. One stock the other gutted. (Track only, officer.) Big difference in power with the gutted and a bit more noise. Every so often I get this spasm to try and be smog responsible with performance. Now, the cut-outs to bypass the cats yet still use the straight-thru muffler is an idea I never considered. (A loud vehicle says come inspect me and give me a ticket. I prefer the sleeper look.) Oh well, mean while I'm starring at all these cats I bought.