they are both 2 1/4", but the diameter is not the problem. the 2 bolt flange that attaches the header to the cat are off center. you have to either cut and reweld the flange on at the correct angle, or get an omni/blox adjustable test pipe. i read somewhere recently that the 90-91 teg cats have floating flanges that allow you to turn them whichever way you need them, but i haven't been able to verify this personally.
in the rush to let you know .... and yes they gona bolt up like butter .... at least that s how it owrked for me and i had a jdm b16A2 motor with the 00 wiring harness and my boy repined it , to work but my motor was a japanase b16 from ja--paaaaaaaanaa durrrrrrr but the exausta does work out well i went 2.5 inches from cat back and as far as the cat goes i li ve in florida now and there is now laws regarding the exaust
but when i lived i pa and i honestly had the same set up as i do now and what i did was took out my o2 sensor .. smoked a dubie
and put a condoem on the o2 sensor( im a bad speller)
which was a commonly sold item at auto zone which is a metal condom
literaly its a metal condom
and it will settle your electrical issues .. .
ps ...... niggers
they are both 2 1/4", but the diameter is not the problem. the 2 bolt flange that attaches the header to the cat are off center. you have to either cut and reweld the flange on at the correct angle, or get an omni/blox adjustable test pipe.
the b16 header flange appears to be angled differently than b18 ls headers cause mine doesn't sit like that, and i assumed all b-series header flange angles would be the same... regardless, it appears that the bolt holes are off by enough to prevent you from bolting it up properly. you can see in this pic how i ghetto rigged my old stock header to my old exhaust due to the holes not lining up. i have a new header and new catback now, with a blox test pipe.