quote:Originally posted by No Quarter:
Doug, do you know the ratio in my Longchamp?
No. I know little about the car itself. Consider though that the Pantera is 4.22:1 with a 2.20:1 first gear. When you multiply those numbers it comes remarkably close to what a Mustang with a 3.89:1 rear and a 2.32 first gear has.
I can tell you from experience though that if you want the Mustang to pull hard enough to break a 15.0 second 1/4 mile you really need 4.33 rear end ratio with that transmission.
Automatics complicate that formula though. Generally they have a lower ratio first gear and the torque converter because it slips some, adds more rpm to the engine at that point. As if the car had lower gears.
If I remember correctly, a C6 with a 3.50 rear is approximately equal to the 3.89/2.32 manual ratio?
Some people have been successful with using the 78 or so Granada transmission in the car since it has an overdrive top gear. This gives you the bottom end that you need and recovers some of the lost gas mileage at the top because of the increase rpm.
Any way you look at it though, looks like if you got around 12 mph, that's going to be about the best you can do with that car and engine setup.
It wasn't built at a time when high mileage was a major concern.