Reply to "ZF Horsepower Rating"

Sorry- you cannot compare 62-67 GT-40 ZFs with the later units used in passenger cars. Early ZFs used in GT-40s and a few Mangustas were physically smaller; the aluminum cases alone weigh 15 lbs less than the ones used 'upside-down' in Panteras. Two more bolts were added in the clutch area and one more in a slightly larger bolt circle on enlarged bellhousings. Early racing ZFs used aluminum side-plates which in an enduro-racing situation heated, expanded and relaxed differential side bearing preloads leading to "ZF trans failure". All Panteras and most Mangustas got ductile-iron side plates. I run a pair of the original racing aluminum side plates on the street (for a 12 lb weight loss) and they work fine in a street application.

I instrumented our ZF: it took over an hour of running on Nevada desert highways at way over the 70 MPH limit to get the ZF to barely 180F. Gt-40s and GR-4 Panteras needed tranny coolers and aux. pumps to allow the system to survive (300F) in 3 to 6 hr race conditions. And my setup is with a 'street' ZF using heat-producing clutches in the LSD; GT-40s used a one-way LSD similar to a Detroit Locker that heated the lube much less but was noisier & wore much faster.

There were at least a dozen high-powered BBC street conversions built in the '80s by Bonneville's Mike Cook; at least one is still running around So-Cal. Within the last dozen years, quite a few BBF conversions have been done by the Byars Bros; one street car has a 545 cube assembly with no ZF problems. He's run the Nevada Mile two years so far, trying to break 180 from a standing start after driving there from Nor-Cal and back. He's getting close. Several others have a 514s. One drove to 'Vegas from LA a few years ago and ran an open track event, then drove home- all with zero problems.

I could go on.... but experience shows that a 5DS-25/2 ZF WILL handle about 750 bhp ON THE STREET. It may NOT survive pro enduro racing although several real-racers currently run the 3hr-long Classic LeMans each year and one was clocked repeatedly at 195+ on the Mulsanne straight. Incidently, a Ricardo won't work in a Pantera unless you feel up to rebuilding the entire rear clip. The 210-lb, 1000-horse-rated Ricardo trans is 3" too wide to fit between the Pantera's frame rails, where the rear suspension attaches. I know of 1.0 Pantera running such a thing (with a Ford GT engine) and the installer said he never wanted to do another. A late Porsche turbo transaxle probably makes more sense than a Ricardo.