I need to know what length catalytic converters you are running. I'm going to be getting a JDM 2.5" header and I need to know the lenght of the cat I need to order. I've been told that it's probably 17" but I need to be sure before ordering it. Thanks for the help.

 

if you have a b series header on the engine right now it should be the same exact setup just with a larger cat, i switched over from my stock manifold to a jdm 1st gen header by tunabe and it was the same other than about 5 mm to short. also before this was on my stock cat was lengthened about 2 inches

 

If the header you were using was a 2" collector then it's the same length as the US headers. The JDM 2.5" headers are longer than the headers with 2" collectors.