1986-93 Mustang BBK Catted X-Pipe for Shorty Headers - 2.5" - 5.0 by BBK

I bought an '89 GT that had an off road Y-pipe with stock mufflers so that all had to go. I bought the BBK cated X-pipe with the Flowmaster Cat back system. Not only did it pass inspection, it sounds great and seems to have a little more low end power. Installation could not have been easier to my existing shorty headers.

I recommend this product with the following advice:
With some minor modification and a bit of forethought, this product fit around the T56 Transmission installed in my ’90 Fox - that was excellent!
The construction is good to very good, depending on if it’s the result of human hands, or not - some of the welds were pretty sloppy, but there were no voids or burn-throughs. I mounted the x-pipe to BBK Shorty headers and didn't expect problems; however, I had to use a round file to open the bolt holes on the left forward x-pipe flange - the spread between the studs on the left header was too close, by about 3/16 of an inch, to allow the x-pipe flange to mount so either the header flange or the x-pipe flange was out of tolerance.
The left side mated to its x-pipe sister perfectly, but the right side down pipe left a wide space: There is also about 1- to 1.25-inch difference in length, either between the left and right down pipes or the left and right pipes extending forward from the crossover "X".
The coupling design favors a miss-match, and that’s okay because header/exhaust systems have always been a pain to install and the couplings work great to bring things inline. Unfortunately, the coupling also allows BBK to cut the corner on quality-of-fit. If the coupling doubles as a sealing device between miss-matched pipes, a smaller gap would certainly lessen potential leaks.
It's hard to say if this is intended or not because instructions don't address the issue and I won't have the Cat-backs in for some time. Until I do, won't be able to say if one down pipe needs trimming, the other needs an extension, or both need more work.
I think someone with less automotive experience would be greatly disappointed in the fit of this product; that’s an unfortunate appraisal for a product made in the USA and one that doesn’t fare well for BBK - I had to rework sloppy welds on their headers, too.
I recommend this product with the following advice:
With some minor modification and a bit of forethought, this product fit around the T56 Transmission installed in my ’90 Fox - that was excellent!
The construction is good to very good, depending on if it’s the result of human hands or not - some of the welds were pretty sloppy, but there were no voids or burn-throughs.
I mounted the x-pipe to BBK Shorty headers and didn't expect problems because they came from the same manufacturer; however, I had to use a round file to open the bolt holes on the left forward x-pipe flange - the spread between the studs on the left header was too close, by about 3/16 of an inch, to allow the x-pipe flange to mount. Either the header flange or the x-pipe flange was out of tolerance.
There is also about 1- to 1.25-inch difference in length, either between the left and right down pipe, or the left and right pipes extending forward from the crossover "X". The left side mated to its x-pipe sister perfectly but the right side had a wide space.
The coupling design favors a miss-match between these two parts, and that’s okay because header/exhaust systems have always been a pain to install and the couplings work great to bring things inline. Unfortunately, the coupling design also allows BBK to cut the corner on quality-of-fit. If the coupling doubles as a sealing device between miss-matched pipes, a smaller gap would certainly lessen potential leaks, and I would expect no more than 3/16-inch space.
It's hard to say how much miss match is allowable, if any, because the instructions don't address the issue and I won't have the Cat-backs in for some time. Until I install the rest of my exhaust, I won't be able to say if the left down pipe needs trimming, the right side needs an extension or both need more work.
I think someone with less automotive experience would be greatly disappointed in the fit of this product; that’s an unfortunate appraisal for a product made in the USA and one that doesn’t fare well for BBK - I had to rework sloppy welds on their headers, too.
On the other hand, as I said previously, this set of x-pipes installed well with Stiffler's T56 Cross member and my T-56 transmission. You will need to modify the EGR return line and the hanger rods for that application but no one at Stiffler's, BBK, or any of the Parts Stores could give me this information - it could have been an expensive purchase but now the info is out there for others, and they can spend their dollars as they need to.

Put this x-pipe on my '90 7-Up convertible along with BBK shorty ceramic coated headers and flowmaster force II cat-back. Overall sounds is very tinny and not too loud. Definitely a better sound than stock! Also noticed a seat-of-the-pants power increase and the engine revs quicker even with my stock 2.73:1 rear end.

Did have to send the first set back due to shipping damage on one of the flanges.
I'm also not sure there is a ton of benefit from going to x-pipe over h-pipe but I can't really compare as I had a stock 4-cat h-pipe on before and this is definitely a lot better!

I bought this for my 92 LX and installed it in less than 40 minutes. It was a perfect fit to include the location of the 02 sensors. Even though it is catted it still improved the overall sound of my baby and you can tell it flows way better. This replaced my 25 year old mid pipe which had four cats total. Perfect fit, better performance and a super easy install.

I purchased this on 4/23/15 and already blew out drivers side converter sounded like there was loose bolts under drivers seat!
But one call to BBK in Temecula Ca and received another set under warranty