1964 Chevrolet shortbed Stepside pickup - Done With Gears - Tech

Any time one runs across a custom classic truck that has been in the hands of the same owner for many years, it is always interesting to note the changes both the owner and the truck have undergone. It seems the more radical the truck was built in the beginning, the less the owner tends to enjoy it as he ages, and almost without exception the truck is driven less.

Such was the case for Jerry Sievers of Placentia, California, and the '64 Chevy shortbed Stepside pickup he has owned for the last 30 years. Complementing the '64's classic hot rod looks, the drivetrain in Jerry's pickup is a 327 with three deuces backed by an M-21 Muncie four-speed hooked to a set of deep 4.10:1 gears. As we all know, deep gears are a lot of fun when it's time to leave someone sitting at the stoplight, but the fun starts to wear off as soon as one hits fourth gear and the engine is still screaming like a banshee. In addition to the wear and tear on both the engine's internal components and the driver's nerves, an engine sustained at higher rpm burns a lot more gasoline and ultimately wears out faster.

Jerry considered dumping his four-gear Muncie in favor of a late-model five-speed, but in addition to losing a major part of his '64's nostalgic appeal, he was concerned installing a five-speed with its wider ratios would hurt his truck's performance. A standard five-speed would drop the rpm by 40 percent on a first to second gear shift, which means when winding first to 4,000 rpm and then shifting to second, the tach would drop to 2,400 rpm. To give an example of how wide a jump that is, skip-shifting an M-21 Muncie from 4,000 rpm in first to third gear will drop the tachometer to 2,327 rpm.

Before Jerry installed the Gear Vendors Under/Overdrive unit, the jump from 4,000 rpm in first gear in his close-ratio M-21 Muncie would be to 2,981 rpm in second gear. After installing the Gear Vendors Under/Overdrive unit, shifting from first gear at 4,000 rpm to first gear overdrive will drop the rpm to 3,120. When we asked Gear Vendors about the effect of a clutchless power shift from first gear to first gear overdrive, they explained, "Since the vehicle actually is gaining speed during the Gear Vendors shift (no clutch depression), you actually would never see less than probably 3,300 rpm."