Reply to "ZF Horsepower Rating"

From my point of view every aspect of the Pantera points to a sensible limit of about 500 bhp as a GT car (i.e. on street tires). 500 bhp was a lot of horsepower in the late sixties when the Pantera was designed, especially in the world of road racing and endurance racing. I don't know if there was a "goal" when the car was built, but certainly if they felt the car could stand up to 500 bhp the designers would have felt it was "state-of-the-art" in that time period (for instance, the 351C was designed as a 515 bhp @ 7000 rpm race motor). If an owner is going beyond 500 bhp they should plan on making substantial alterations.

What I have heard over and over again from people who have raced the Pantera is "The Pantera is a GT, not a race car". In other words the Pantera requires a lot of re-engineering to turn it into a competitive race car. If an owner is using the car in racing conditions they should plan on making substantial alterations too.

Lloyd Butfoy will guarantee his rebuilt ZF's to 550 ft/lbs of torque, he doesn't use a horsepower figure. I have heard of ZFs bolted to Big Block (500 cubic inch) crate engines spitting gears through the cases. If I remember properly, fourth gear needs direct lubrication at elevated horsepower. I think Ron nailed it pretty good, about 700 bhp is the limit I am aware of people reliably using the ZF in racing conditions. The ZF needs the gear oil circulated through a heat exchanger too when racing it.

But the transmission is only one aspect. Even if you replace the gearbox, there are other areas of the car that will need to be re-engineered. I can think of two at the moment:

The foot print of the Pantera radiator is good to about 500 to 550 horsepower according to Evans Cooling. Going above 500 bhp in a racing application means gutting the front of the car to fit a larger radiator.

The monocoque chassis structure needs reinforcement anytime you slip racing tires on the car, or when you increase the motors output. the rear suspension & engine substructure twists significantly, and the A pillars will try to detach themselves from the front fender/firewall. Up to 500 bhp the street cars do fairly well with the chassis braces sold by the Pantera vendors. Guys racing their Panteras with more than 500 bhp usually make substantial alterations to the chassis, such as installation of tube sub-structures, or tying the whole chassis together via an elaborate roll cage, etc.

-G