[JayBar]

My first engine was a 351 AFR heads stage II trick flow cam and it dyno'ed at 326 RWHP. MY rear was a 3:10 open differential. Transmission was a T-5 (turns out from a 6 cylinder mustang).
My best track time was 12.2 et at 112. That engine went south doing an open track event (check my pics). My new engine a dart block 408 CI, same AFR heads stage III cam, victor Jr. with a 950 cfm Holley HP. Changed my rear to 3:73 with three clutch packs added. And a TKO 600 with a .68 5th gear. Dyno'ed at 428 RWHP.
Trip to the drags. Best of 12.2 at 120mph. Now this could get better but it is such a hassle getting through tech inspection at an NHRA track that I don't bother anymore. I use the car mostly for open track events where it eats German and Bow-tie cars (except for new Z06's). I am thinking about changing the 5th gear to the .82 because on a long straight I wind out 4th and a shift into 5th sounds like the engine goes to sleep. The best thing would be to have a T-56 6 speed but my BDR is older and would need trans mission tunnel mods, which I don't feel like doing.

Bottom line, for around town and some spirited highway driving your stock 3:15 rear will be fine. I would seriously question the 500 hp number, sounds like you should have something like 300-350rwhp.