Auto Racing: 82 Ford Mustang Gt 5.0L 302HO exhaust, production tolerances, ford mustang

Question
Hello John,
I was wondering if you could help me with a small problem I'm having. I just set up my brother's 88 GT with BBK chrome headers, BBK off road h-pipe and a Flowmaster American Thunder cayback exhaust. Needless to say, it sounds truly bad! Now, the problem I have is with my car. 82 Gt. I took a set of 85Gt stock headers along with my brother's old stock h-pipe and exhaust and tried to hook it up to my car since it came with a single y-pipe exhaust. After installing the headers, I tried and tried to get the h-pipe to match up, since the headers were essentially the same as the old manifolds, just better. What I found was this. The h-pipe wouldn't line up with both flanges. A little bending and willing it to work and they lined up just right. But, the big problem is the flange on the passenger's side. It won't line up so I can get both nuts started. After much looking and hoping it would fix itself, I realized the old manifolds had their bolts rotated just a little bit different than the new headers. So, it amounted to them being off by about a quarter to half inch. So close and I couldn't get it to go in to the flange. To make matters worse, the flange was hitting ever so slightly on the starter housing. I'm thinking of splicing the old flange off the y-pipe and transplanting it to the h-pipe to get it to fit. But shouldn't it be a direct fit since the 88 and 82 are essentially the same engine and same starter location? There is a difference of 1/4 inch in the size of my old exhaust to the size of the newer one I'm trying to put in, could that be the problem? It's driving me crazy why I've spent hours and still can't figure this thing out. What started out as an easy swap turned into a project that I just can't wait to finish now. Any ideas you may have would be greatly appreciated. Thanks for your time in reading this long question.  

Answer
Hi Mike ,Well witout seeing this it's a little tough ,but there are production tolerances and a 1/4" isn't that far off that a bit of heat might change,would slotting (enlarging) the holes in the flange help? a trip to a shop with a bender(with the car or even just the pipe) might help .I wish i could be of more help ,Good luck on this problem ,Jmazio