The Amazon bearing is nice but how does it work as a bearing if it isn't press fit to the ZF input shaft?
It would be acting as a "bushing" and the input shaft would just be spinning in the bearing race otherwise?
It is like an axle bearing and those need to be pressed on the axle shaft. Zero clearance is a press fit.
The Ford bushing needs to be tapped into the crank with a wooden block to seat it. So maybe it is .001" smaller?
I can't say as I have seen any Ford "bushing" oblong ever and 50,000 mile Panteras are kind of rare? Sometimes memory seems all to convenient? I also doubt you would get 50,000 miles out of the original clutch especially considering the nature of the car? I'd think 30,000 to 35.000 miles is more like it?
A roller bearing has more potential of freezing or rusting in place from disuse and I HAVE seen the "seal" on the sealed axle bearings come loose and self destruct as a result.
I personally appreciate everyone's good research but I just have to say that an "machined oilite bronze bearing/bushing" is just one heck of a brilliant solution!
I wouldn't necessarily put a lot of faith into what was originally used in the GT-40's. They really were never intended to be anything but endurance race cars.
They were all torn down after every race and rebuilt so there is very little likeliness of needing to last 50,000 miles.
In a street car the pilot bushing only needs to last as long as the clutch does.