I am going to try and go with a roller bearing,
Before you go that route, please consider this advice recently posted by Jack DeRyke on the POCA forum:
> Can someone educate me regarding the difference? Are they (bronze
> bushings vs needle bearings) interchangeable?
> Is one more durable than the other?
They are interchangeable but needle pilot bearings are arguably not healthy
to use in a normal Pantera. The pilot bushing/bearing runs in one of the
most hostile areas in your car for bushings or bearings, with high heat from
the clutch and engine, pulsating loads, complete lack of external lubrication
and abrasives from clutch wear. A self-lubricating bronze bushing is a
sliding-friction unit while a needle bearing is a less tolerant rolling-element
assembly. A soft bushing will wear out in maybe 30,000 miles. A sealed
needle bearing will not wear but it may seize from the adverse conditions. If it
seizes, the hard bearing race will gouge the nose of the softer clutch-input
shaft of your ZF- or thrash out the holev in the crankshaft, and you really
don't want to know what THOSE cost to replace. I've replaced clutch input
shafts in U.S made transmissions from this defect and they were 'only' $125,
not including the tranny removal and a complete tear-down. In cars that get
frequent maintenence and inspection, needle bearings would work. But on a
normal 'hasn't-been-touched-since DeTomaso-built-it' Pantera, they can lead to
tears and much expense. Some trucks do use needle bearings in that
location, but they are almost always low rpm engines, and being work trucks they
usually get frequent maintenence- and I suspect the needle bearings are still
changed each time the engine or transmission is removed, just like the
cheaper bushings. Most pro race cars don't use needle bearings there, either...
and if they were 'better' or had any advantage, one would think professional
teams would use them.
So, bottom line- it's a personal choice with some risk involved. Neither
can be installed and forgotten. LLoyd Butfoy of RBT Transmissions could
probably give you real numbers on gouged and replaced ZF input shafts and their
costs. For the rest of us, its an insurance thing. To paraphrase Clint
Eastwood's Dirty Harry Callahan, 'how lucky do you feel today, Charlie?'
Good luck- J Deryke
And a follow-up from Mike Drew:
Last time I heard of one needing to be replaced (more than ten years ago),
the input shaft (which also incorporates first gear as an integral part of
it) was $2500. This knowledge came to be because some guy shipped a ZF in
pieces and failed to pack it properly, and the input shaft punched a first-gear-sized hole in the box and disappeared enroute, never to be seen again...and UPS wouldn't pick up the tab because the fellow had failed to insure the
box for the full amount. :<(