Help the new guy!

['84-5.0-LX]

Hi folks,
I can't thank you all enough, you've given me some really good input. First things first, we're looking at an off-road H-pipe with Flowmasters, probably Deltas (no inspections around here so why not go off-road) and our guy at the local shop found us some factory Mustang headers off of an '86 that he thinks will work just fine- not super-efficient aftermarket ceramics, but cheap and much better than the existing manifolds. The gears are something I hadn't even considered, but sounds like an excellent next step after exhaust. I'm thinking 3.73 will do us real nice. I'll be sure to let you guys know how everything works out, thanks again for the input!