Question about dual-cat h-pipe

[Vatchy]

I bought an almost new Mac dual-cat h-pipe from a guy that used it once on his '87 (or later) Fox. When I found out that it wouldn't fit, I bought a non-cat h-pipe from Summit to replace it. It doesn't fit, either. I called Summit and they said that nobody makes an h-pipe for short-tube headers for an '85.

My question is, what could possibly have changed between the 1985 and 1987 models to make the h-pipe not fit? I have '87-'93 shorty headers on it and they fit perfectly. They're basically the same car with basically the same engine.

I finally just took the car to an exhaust shop and let them build the h-pipe. Not what I wanted, though.

 

[Bullitt347]

The trans crossmember the clearance issue? Along with that, the hanger that bolts between the trans crossmember and the trans mount?

 

[Vatchy]

No, the bends in the h-pipe put the exhaust ends too close to the undercarriage.

 

[Mustang5L5]

I bought an almost new Mac dual-cat h-pipe from a guy that used it once on his '87 (or later) Fox. When I found out that it wouldn't fit, I bought a non-cat h-pipe from Summit to replace it. It doesn't fit, either. I called Summit and they said that nobody makes an h-pipe for short-tube headers for an '85.

My question is, what could possibly have changed between the 1985 and 1987 models to make the h-pipe not fit? I have '87-'93 shorty headers on it and they fit perfectly. They're basically the same car with basically the same engine.

I finally just took the car to an exhaust shop and let them build the h-pipe. Not what I wanted, though.

Did you ever see the original headers on the '85?? One of them (passenger side) has a vacuum-operated flapper in it to make the car warm up faster by blocking off exhaust gases. Because of this, the passenger side header flange is larger and located lower. An 86-93 H-pipe will not bolt up to it.

However, if you replace that header with an 86-later header and install a dual-hump crossmember, you are good to go at installing a true-dual system like an 86-later using off the shelf parts.

I beleive te '85 driver's side header is the same as 86-later


86 later headers, h-pipe and cat-back should all fit fine. Where did you have your issue of not fitting

 

[Vatchy]

Did you ever see the original headers on the '85??

Yes, I still have them.

One of them (passenger side) has a vacuum-operated flapper in it to make the car warm up faster by blocking off exhaust gases.

I may still have that, although I may have thrown it away, since it came off when I took the headers off.

However, if you replace that header with an 86-later header

Yup, did that.

and install a dual-hump crossmember,

Did that, too.

you are good to go at installing a true-dual system like an 86-later using off the shelf parts.

Nope, that's why I asked the question in the first place. I tried two different h-pipes and they both don't fit in exactly the same way.

 

[Mustang5L5]

That's strange. They should have. Where didn't it fit exactly?