Quote Originally Posted by Dickbag 5.h0 View Post
No need for axles or track lock, even at higher power levels. The Ford 8.8 rears are tough sob's that will endure a lot of abuse. I've pounded the stock rear in my 2000 GT for years with over 400whp and it hasn't missed a beat. Take that cash and put it towards an aluminum driveshaft.

I'm running 4.10's and they work great for my application. At 65mph its revving around 2400rpm with a 25" tire in 5th. Coming thru the traps its at the very top end of 4th gear(6k rpm) at 124mph on a 26" tire. Not sure if the Mach and GT share the same gear and final drive ratio's, if so, I think you would be happy with either gear. If your careful removing and installing the axles after your gear change you don't need to replace your seals or bearings if both are fine.
I see your abuse and raise you a pinion

4.30 Ford gear(made by Motive)