Reply to "#1493 motor update"

71HI, if you have some money left from your purchase, save it for a dash-2 ZF. Your 'dash-1' is actually what Lloyd Butfoy at RBT Transmissions calls a 'dash 1-1/2' since a true dash-1 ZF is only found in the Mangusta. What you have is a Pantera differential case flipped upside-down from the GT-40/Mangusta style, with a Pantera 4.22:1 ring & pinion inside, and a Mangusta transmission & gears bolted on. The factory did this on not-very-many preproduction prototype '71s before ZF got all the new tooling finished to Fords liking for production cars, in mid-1971.

About half the guts of transition ZFs are specific to the early Pantera and the Mangusta/GT-40, and very few spare parts are available. The mainshaft is longer, the clutch spline is 1-1/16"-10 while dash-2 clutch discs are 1-1/8"-10 so clutch discs are different, the bellhousing is a smaller and lighter sand-cast unit with two small access holes and fewer bolts, and several of the gears inside are different. As you noticed, the rear ZF mount is different, too. The ZF may even have a non-clutch-type LSD inside, for which NO replacement parts are available. If ANYTHING goes wrong with that box, a normal ZF rebuild isn't going to be as "cheap" as on a dash-2, if it's even possible. A few used parts will of course be available but possible interchanges that fit the early box are not well known outside of RBT. Call him sometime and ask about all this. I am not a real expert although I've worked on both types.

If your transition ZF is shifting OK and not noisy or dripping, drive it (carefully) as-is until you find a dash-2 you can afford and have that checked over. Then swap the ZFs- they are bolt-ins. Note you will also need a later bellhousing, cross-shaft and all the internal clutch release parts too as they're specific to each type of bellhousing. You'll need a later clutch disc as well. Your clutch slave cylinder and bracket may work as-is.

As for your lifter bushings, it depends entirely on what size oil holes are in the bushings as to whether hydraulic lifters will be noisy or not at low rpms. Some engine shops install bushings to blueprint lifter bores, which are often not perfectly positioned in any production engine, and available blocks nowadays often have worn lifter bores. A bunch of worn lifter bores contribute to low oil pressures; bushings can correct both problems. For racing, I'm told an 0.090" oil hole is often used in bushings while for street use, maybe 0.120" or slightly larger gives more oil flow for hydraulics. Stock was about 0.375"! Bushing holes can be opened up with a complete engine teardown.

You'll need to dig into the motor to find what actual size oil holes are in the bushings, but bottom line- if there's no rattling noise at idle with hydraulics- either roller or flat tappet, you're likely good to go. Doesn't Hawaii still have a state-wide 45 mph limit?