Did a search and didn't really find what I was looking for. What size is the SLP 1 5/8 and 1 3/4 headers where it bolts to the Y pipe? What about the Hooker 1 5/8? Are they a true 2.5 flange?

What about the size of the Y pipes for each where it mounts to the cat? 3"?

Thanks

 

The 1 5/8 and 1 3/4 are the primary tubes on the headers how big they are. On the slp y pipe it meets up into a 3 inch colector so you should go ahead and pickup a 3 inch cat when you put it on.

 

I think he means what size are the collectors on the headers. The SLP collectors are 2.5 I think and actually neck down to about 2.2 inside the header with 2 1/4 pipes into a 3 inch collector, but you also must buy the cat adaptor to hook up to your cat. The hooker 2055's have a 3 inch collector, but where it meets the y pipe it is actually a very small 1.9-2 inches, but this is very easy to remedy. All you have to do is grind it open to the ID of the y pipe. The Hooker y pipe has 2 2.5 inch pipes into one 3 inch pipe where it mates to the cat.

 

Thats exactly what I was looking for.