The 5.25:1 rear is usefull if you are going to drag race the car and use it as a 4 speed.
Gary Hall put one in his GTS and had Mike Cook drive the car into the 9's in the 1/4.
The ratios in the -1 I think are better street ratios simply because there is a better 1st gear ratio at 2.41, I believe.
The 3.77's that came up "recently" were from a batch of GT40 sets that were in storage from the 60s.
This is not a 200mph+ vehicle. There is no point to me in using them. It will kill the first gear launch.
Considering that Botfoy gets $4,000 for a new ring and pinion set, an RBT 6 speed would be a better approach BUT that essentially is just adding a low first gear and maintaining the top gear as overdrive of .7:1.
Then you can have t10 type close ratio spacings, a 3.27 first gear for nose pulling launches AND a high speed over drive gear.
For a high performance vehicle in reality, not talk, you want a first gear and final drive ratio to produce a number around 11 to 1 when you multiply the two. Depending on the weight of the vehicle the "generality" is a number of at least 10.
If you look at the Ford Mustang with a 289HP engine, look at the 2.32 first gear, the 3.89 final drive, the product of those two numbers is 9.02.
I think the Pantera's design acceleration is modeled after the 289HP Mustang. It is NOT fast. It is a 15 second 1/4 mile car.
The Pantera is 9.284 with a -2, 10.170 with a -1 ZF.
This is Ford Engineering's involvement in the Pantera. They were afraid putting the potential for acceleration in the hands of the public, so they neutered the car somewhat with a BAD first gear ratio.
What "you" want is probably a 2.80 to 3.25 first gear, a product of about 11 when multiplied by the final drive would be a great launch ratio.
You work the ratios of the gear box with this all in mind. If you want to plan for 200mph at top speed then at what rpm, I suggest 6,800 rpm, and calculate the overdrive that way.
For me 5 forward gears are enough. 6 I have very little use for.
If you want a nice low level hum so you can sleep when you are travelling, put in an electric power train with automatic sensors for everything. Better yet, get a limo with a Chauffer and sleep in the back or watch tv?
