I know using SSAC is a no-no, but has anybody used a SSAC 3" SS o2 housing before? I really need a 3" o2 housing and it's either SSAC or custom made. I also figure is i need to, get the joints rewelded....

 

I guess by saying SSAC o2 housing you mean downpipe? Just buy a flange and some 3 inch piping and make your own 3 inch downpipe,SSAC downpipes are usually not the size they advertise them to be either.... but its up to you.