All the clutches on RockAuto are diaphragm, with the exception of the ACDelco 3-finger (Bog & Beck style) listed for some applications. Diaphragm pressure plates were designed for lighter pedal pressure--to make the clutch easier on the left leg--and do not have the holding power of a Borg & Beck or Long design. This usually isn't an issue with a stone-stock application unless you're doing a lot of towing. However, as you get into higher horsepower it does become more likely to slip. In a lot of cases, it's a personal choice. Diaphragms are spongy and undefined; with a B&B, and moreso a Long, you can feel the clutch's internal leverage working. If you're looking for performance use the only diaphragm worth knowing is a Centerforce due to its centrifugal weights. They increase plate loading with RPM (and increase clutch effort as they do). It's a good compromise. One thing to remember if you choose to use a diaphragm pressure plate: You must remove the over-center spring from the clutch pedal. Even the Centerforce will hang on the floor in "good-time party shifting" if you leave the spring in place. They just don't push back hard enough to overcome that spring. Centerforce tells you this; LUK and others do not. Now, for your consideration: That spring does a lot of the work for you when pushing the clutch pedal, so you may find that removing it and using a weaker diaphragm clutch results in similar pedal effort to running a stock-type Borg & Beck pressure plate with it.
For anyone considering using hydraulics to operate the clutch, check either the original application's clutch design (OE parts) or get hard numbers from the manufacturer (race stuff) to make sure your master & slave cylinder can handle the type of clutch you'll be using. The hydraulics on a Dakota, for instance, will not last with a 3-finger pressure plate of any significant plate load. The old iron stuff from '60s Dodge trucks would probably push through a brick wall, on the other hand. :icon_biggrin:
If you're using clutch linkage, forego the factory passenger-car arrangement at the fork adjuster rod and use the metal ball & associated pieces from a Dodge truck. PGClassics in Canada sells their fork adjuster setup for the muscle-era stuff with the good stuff already on it, and the price is downright bargain basement ($16+shipping). It works on our cars too. If you're not interested in concourse restoration, a lot of the restoration stuff such as brackets, boots, z-bars, and pushrods can be modified from other applications and can be had pretty inexpensively. PG sells reproduction Z-bars for under $50; cut one arm off and reposition it correctly, possibly trim the tube, and install. Better than paying top-shelf price for a rusty original if you ask me.
The A & F-body cars have the shorter tailshaft needed for the swap, but if you can get it with the shift linkage in place, or make sure the seller knows what he's got when you're shopping. A-bodies were available with both close-ratio and OD transmissions in '75-'76; all F-cars were OD. Simply put, the close-ratio 3-4 linkage rod from an A-body will not work without modification on an A/F-body OD transmission and vice-versa. The other linkage rods can be made to work. Replace the crappy Inland shifter used on OD transmissions with a Hurst Competition Plus piece from just about any Mopar application. Optimally, you'd get your hands on a set of rare Hurst Comp Plus rods for the overdrive transmission... but don't hold your breath.
