I am considering the following two options to finish out my exaust system on my 91 350 formula. I a looking for performance and sound, the car is not a daily driver and I do take it to the track about once per month. This would go with Borla 3" catback (already installed) and either Hooker or Edelbrock coated 1 5/8" headers

1. stay with dual cats and buy this, part number cto-4153

http://store.summitracing.com/defaul...rchType%3DBoth

It is a stainless steel bolt on catco dual cat replacement. It comes with the pipes to connect fromt the cats to the headers so I could by headers without those pipes, like uses. The pipe I belive are only 2 1/4" or 2 1/2", but there are two cats to flow through.

2. Buy the headers with a y pipe and get rid of the two cats and go to one catco big cat. The pipes that come with these headers are I think 3" right? This way I would only have one cat, but I could put in a cutout before the cat and run that way when going to the track. With the dual cats there is no place to put a cutout before the cats, you would need two and they cant face down due to ground clearance and the pipes are right next to each other.

Which of these two do you think would give better performance. I kind of hate to lose the two cats, but I gain the cutout.

I just noticed that the size on stainless steel dual cat setup is
2 1/4" in and 2 1/2" out, I guess that is stock

 

I'd go with the single 3" hi flo cat.

 

Just wondering why? Looked at your site, very nice car and very nice site. I like the links to the individual companies like Moser etc. I assum you think the larger pipes between the headers and cats, and the fact I could use a cutout, outweight the disadvantage of one cat vs. two cats