air fuel meter with O/R H Pipe
 

I was wondering if any one would know if i could still use and air/fuel gauge after installing a O/R H-Pipe

I believe so because isnt the a/f ratio read before that point? I dont know wether they are read pre or post cat on the Mustangs but it should be fine. If someone knows 100% feel free to jump in.

if you get a a/f ratio gauge like i did, they always tap into the o2 sensor before the cat. i don't think i've seen it anyother way, unless you get one of the special ones that you tap your exhuast or it comes with a special o2 reader that you put in the exhuast.
The autometer ones, comes with a red wire(12v source) black (ground) purple ( signal wire on your 02 wire harness(don't use the wire harness from the 02, use the wire harness from the car) if you don't know your signal wire, looks into a haynes manual and it'll tell you.

thanks alot for the help!!!!!

That's what we're here for....:beerchug: