Dynatech Exhaust - 07-11 Mustang Shelby GT500 & 05-10 GT PoweCat converter/4 bolt collector adapter for Dynatech LTs 2.5" Pair of 4 bolt flange collector adapters with high-flow Powercat catalytic converters to mate up to Dynatech LTs. Includes donut gasket set and bolts. 2.5" ID slip fit connection, ideal for mating LTs to factory 2.5" X pipe or H pipe on 2007-2010 GT500s or 2005-2010 Mustang GT 4.6L 3V (requires cutting stock H/X pipe behind the factory cats).