85 headers and true dual exhaust

[Dogster]

Has anybody put a true dual exhaust with dual cats on a 5.0 with the 85 headers and exhaust heat manifold heat control valve? Does anyone make a catted h or x that will fit the 85 headers? I'm registering my 85 GT for the first time in CA and have to pass smog to register it, so I need to keep the exhaust manifold heat control valve. I figure they'll probably look harder at an out of state vehicle the first time they smog it. My Y pipe and tail pipes have rust holes in them. Plus I believe my cat/cats are bad. So I need to replace the entire system - but don't know if I could sneak through smog with 86 and up shorty headers. Is using 85 headers and a dual catted H pipe feasible? I know it's not technically legal but from what I've heard the techs don't know the 85s didn't have true duals. I don't want to put a new 85 single cat/dual muffler system on it just to dump it after I pass smog. Any suggestions?

[Curtis]

I used a catted BBK H Pipe on my 85 with the original 85 headers and had no problems other than it was a bitch to do by myself. I had to grow extra arms and get creative with a floor jack to hold everything in place to bolt up. The only mod I had to do was to elongate one hole in the drivers side flange of the h pipe where it bolts to the header. Without doing this, I couldn't get both studs to clear. Just a slight elongation, nothing major. One year later, no leaks. The only other problem I had was with the 86 and up H pipe hanger at the transmount. After several attempts to install the H Pipe with the hanger already in place, I had to take everything apart (cross member and trans mount) install the hanger on the H pipe first then re-assemble the trans mount and cross member. You also will need to plug the O2 sensor, I sprung for a stainless plug from Jegs, others use a old O2 sensor or a spark plug. This is a very good modification as I immediately felt a difference in seat of the pants and sound is so much better than stock.

One more thing, I may be crazy but the other stange thing about the valve on the driver side header is I swear I can actually hear the stupid thing open, the exhaust note distinctly changes. Only notice it when I just started the car after it has been sitting.

[X-isles]

Dog...I just that exact thing on Friday. I didnt use any aftermarket pipes, I let the exhaust shop build their own.

[Dogster]

Hey thanks for the advice. That's a relief. I'll either get them to build an H pipe or use the BBK. I also wonder if the 85 headers flow more since the collectors are bigger... I looked at JBA but the 85's that are smog legal have 1-1/2s tubes vs. the 86 which are 1-5/8. I will change headers later on when I rebuild the motor. I just need to get through smog now.