Upgrading OE Clutches To McLeod Performance Parts - Clutch Can Horse Tamer

There are two key requirements to a daily driver: It has to be reliable and always ready for action. My "low-buck" '69 Dart, originally a 273/automatic, is now running a warmed-over 318 and overdrive four-speed. Unfortunately, it has recently been a case of "once bitten, twice shy" as far as swapping-in junkyard components are concerned. First, the junkyard OD four-speed turned out to be toast, so it had to be removed and rebuilt ("Overdrive Overhaul," Mopar Muscle, Oct. '01). Second, the junkyard clutch cover out of the F-Body donor car and a Cheap-O Autoparts replacement clutch disc were useless. Though the cover looked like new and the disc was replaced, the clutch simply wouldn't hold torque. An off-the-line dump would smoke the clutch, not rubber, and one-two power shifts would break the clutch so loose it wouldn't catch without lifting.

Though the clutch chattered violently on engagement, the Dart would still get down the road, but when handling impromptu street action, it was seriously handicapped. Delicate movement on the clutch and rolling starts were enough to handle the average contender, but crunch time came when confronted by a 2,600-pound Mercury Comet (Maverick style) sporting a hot Ford small-block. It was as fast as it was ugly. The pull in First gear was bumper to bumper, but counting down the revs as the tach neared seven grand, I knew the gig was up. Slamming Second, the clutch was smoked, and so was my Mopar. The time had come to lose the junk.

We tapped McLeod Industries for the serious hardware. McLeod manufactures the broadest ranges of performance clutches in the industry, with a reputation for quality. We figured with their extensive product line, they would have a clutch component combination well matched to the Dart's requirements.

Moreover, the raw truth is that "routine" 6,800-rpm shifts with the stock flywheel and junkyard OE clutch were attended by nervous thoughts of a metal-and-flesh-sawing clutch explosion waiting to happen. First on the shopping list was a new McLeod SFI-approved steel flywheel. The next decision was the pressure plate style. McLeod offers a full range of covers, including the stock Borg and Beck type, the diaphram style, the Long type, and McLeod's unique Borg and Beck/Long hybrid.

Borg and Beck's come with a 6.0:1 finger ratio and increased holding power comes from a combination of spring-load and centrifugal-assist rollers. The centrifugal assist varies with the number of rollers. Adding rollers increases the centrifugal assist, but the downside is B&B clutches lock up at high rpm. More rollers lock up at a lower rpm, making high-speed shifting difficult or impossible. Hemi cars came with three-roller B&B clutches rather than the six-roller design used in other big-blocks for this reason, and cheap rebuilder's B&B pressure plates often have all of the assist rollers removed.