TTI shorty headers PROBLEM WILL NOT FIT

I was told by the guy I traded a used set of stahl fenderwell headers for the pro parts that they make 30 sets of pro parts a year and when they are out of stock thats it til the next run. Don't know if there is any truth to this though. He is running a 730 hp Indy headed 528 inch rb motor and wanted the larger stahls.