Hot Rod Tech - '58-'64 Chevy Hot Rods Need Driveshaft Upgrades
By noderel:
“Your drive shaft contains all the power your engine makes,” says Greg Frick of Inland Empire Driveline Service (www.iedls.com). “In low gear it delivers engine torque multiplied many times. In high gear it delivers engine torque and peak horsepower, while turning at the same speed as the engine. For smooth, safe operation, you must give serious attention to the driveshaft in your hot rod.”
Frick specializes in a better-than-new two-piece design for full-size 1958-1964 Chevys. “The two-piece shaft set has been troublesome since new,” he said. “Designers made the car lower and engineers had to come up with a way to fit a drive shaft under it. If a one-piece shaft like the ’57 Chevy had would have worked, they would not have gone to the more expensive two-piece shaft.”
Some builders have tried a one-piece shaft in 1958-1964 Chevys and wound up with vibrations, doors that won’t open and even cracked winsdshields. “GM never got the angle right, but we brought the original design up to date using different materials,” Frick says. “We use a stamped steel cast 7075-T6 metal support that looks OEM but has a polyurethane cushion replacing a rubber one.
Frick sells a 4130 steel 1-1/4-in. bearing stub to replace the OEM forging. The Chevy Standard Duty Shaft Set includes a “telescoping” slip fit on the rear section to allow for suspension travel. Originally, axial suspension motion was absorbed at the transmission by means of a floppy rubber cushion at the bearing.
Frick’s stock replacement shaft set uses an OEM-style 1.25-in. bearing stub reproduced in 4130 steel. The set also features a 7075 T-6 center support bearing with telescoping rear shaft to absorb length changes from suspension movement. There is also a “502 Ki” designed for engines over 500 hp. The 502 Kit features a larger 1.5-in. diameter bearing stub, 3.5-in. tube, Spicer 1350 universal joints, 7075 T-6 bearing support and telescoping rear shaft.
Frick said that low riding height isn’t the only reason vehicles use two-piece drive shafts. “Some cars require two-piece drive shafts because of their overall length or because of (undercar) obstacles that have to be avoided,” he explained. “Long wheelbase cars, lowered cars, hydraulic and ‘X’ frame cars all fall into this category, as do long bed pickups and cab-over-engine car haulers.”
According to Frick, two-piece shaft systems are also a means to achieving reduced Critical Speed where long spans exist. The Critical Speed of any shaft is a theoretical number reduced by both the physics at work in the shaft and by the uncertainties of the installation. “While guidelines are published showing recommended maximum shaft lengths at various rpms, judgment is required when these lengths are approached,” Frick noted. “Each vehicle is different and no hard and fast rule applies to all cases; start asking questions at over 51 in.”
All new 1958-1964 Chevy driveshaft solves factory design issues.
Using full rear shaft is recommended to upgrade OEM Chevy design.
Kit includes 1310 Spicer universal joints (1350 for over 500 hp)
All Inland Empire shafts arrive with correct-for-car OEM type yokes.
IEDLS' Jeff Gilroy (L) and Greg Frick can answer driveshaft questions.