ZF transaxle , max torque load

Rest easy; the ZF is arguably the strongest piece in your Pantera! It can and will relably hold up to 750 bhp completely stock with no magic parts or super-oils needed. Racers have done big-block swaps into Panteras, including Jr Wilson's beast that ran a 574" Boss 429 pro-stock engine for years in ORR races. The ZF was the one part that gave Jr virtually no trouble behind 850+ bhp at speeds up to 265 mph.
Brutal shifting in very high horsepower engines can wreck synchros and speed-shift shock loads may shear off trans gear teeth, but reasonable care in shifting will give you no trouble with the transaxle, with almost any power level you can afford.
And if you can handle the $50,000 it takes to get an engine up to this power level- maybe for Bonneville-, RBT has custom high-alloy steel gear sets, reinforced cases, 6-speed ZFs and down to 2.20:1 ring & pinion ratios (stock is 4.22:1).

As far as I know, Lloyd (RBT) will guarantee his rebuilt ZFs to 550 ft/lbs. Gives you an idea what he thinks of their limits.

-G

Hi Bob,

Not only the question of horsepower and torque, but what size and compound of the tires will make a difference in how much force will affect the case of a ZF. Wider, softer tires will bite much more than narrower, harder ones. So if there is a motor out there with 700 horsepower going through 285 wide rubber, you know what is going to happen. Spin, spin, spin.....

What kind of horsepower and torque are you looking at as well as rim and tire selection?

Mark

I've been a member of POCA and PI since 1984 and don't think I've ever heard a single instance of a ZF breaking due to sheer horsepower or torque, in a street driven Pantera. In fact, the only time I've ever heard of a ZF breaking was in the BMW M1 Pro-Car Racing series. The breakage only happened when the M1's were racing on a wet track that was drying out. The huge rear slicks would hit a puddle and spin to 9,000 RPM. The slicks would then hit dry pavement and with their immense grip, would cause a huge shock to the ZF, occasionally snapping the input shaft. In fact, those M1 racing ZF's were fitted with smaller diameter input shafts than the ZF's that came in the Pantera.

Thanks Guys, Great information. Exactly what I wanted!!! I just want a real nice performance car and was Thinking of strokin the motor to a 408 cubes and no were near the torque that you guys are saying for a failure to occur. I'm going to proceed forward with laying out the internal engine parts.I did miss a call back today from RBT transmissions. I just wanted to give them a heads up that the trans axle is on its way, thanks again !!!