Custom Driveshaft – Certified Power Inc.

The project: Hot Rod Regal, perhaps not unlike your project, makes use of many high quality aftermarket parts. These aftermarket parts are designed to perform under different circumstances when compared to OEM parts. It is understood we are seeking higher performance and that some engineering and customization will need to take place to make these various parts from various companies work as a high performance system. One such item that will need to be sorted out is a custom driveshaft. Certified Power Inc. in Bridgeton, Missouri is the driveshaft shop that I called upon to help me with my custom driveshaft needs.
Project: Hot Rod Regal currently has a Moser Engineering 9 inch rear axle package with a nodular iron 3rd member, 1350 series yoke, Detroit Locker and 3.70:1 gears. Making these gears spin will be a TCI automotive Street Fighter 4L60E. The engine mounts are BRP HotRod pieces and the transmission crossmember is a G-Force Crossmembers part. These parts are not going to match up with an OEM driveshaft. A custom driveshaft will need to be made with a new length, a Chevy front U-joint, and a Ford rear U-joint. I contacted Ryan McCormick in driveline sales at Certified Power Inc. (314) 344-3300  to get this ball rolling. This process was very simple and did not “Break the bank”. I asked Ryan what measurements he would need:
  1. Spline count on the transmission output shaft
  2. Outside Diameter of the transmission output shaft
  3. Length of the transmission output shaft past the end of the housing (tail shaft length)
  4. Transmission tailshaft seal size
  5. Ear to Ear length of the rear pinion yoke
  6. Inside or Outside Snap ring required
  7. Center of forward  U-joint to Center of rear U-joint length

I am typically very precise with my measurements and I like things to fit very well.  I used a tape measure and a dial caliper to obtain the following measurements.

Transmission- TCI automotive street fighter 4L60e
  • spline count of tail shaft = 27
  • no key way on spline of tail shaft
  • total length of tail shaft = 5.234 inch
  • length of tail shaft exposed past seal = 0.61 inch
  • seal size = 1.455 inch (number stamped on seal P.I. 8850A)
  • tail shaft O.D. 1.171 inch
Looking forward at the transmission tailshaft, a spline count, O.D. , and seal measurement can be obtained
Looking forward at the transmission tail shaft, a spline count, O.D. , and seal measurement can be obtained
I used the dial calipers to check the total length of the transmission tail shaft. Then I used the tape to measure how much of the tail shaft was protruding from the housing.
I used the dial calipers to check the total length of the transmission tail shaft and the portion extending past the housing. Then I used the tape to double check how much of the tail shaft was protruding from the housing.
Rear Axle / Yoke – Moser Engineering 9 inch with Detroit Locker and 3.70 gears
  • yoke ear to ear length – inside to inside =3.625 inch
  • yoke ear to ear length – outside to outside = 3.888 inch
  • Center to Center u-joint length = 50.375 inch (50 3/8)
  • Transmission tail shaft aft edge to center of Moser 9″ yoke = 52.75 inch (52 3/4)
  • yoke u-joint cap size 1.19 inch
Shown in this photo, the "Ear to Ear" measurement was obtained. Also, the Yoke clearly shows that an internal snap ring will be needed for the rear 1350 U-joints
Shown in this photo, the “Ear to Ear” measurement was obtained. Also, the Yoke clearly shows that an internal snap ring style rear 1350 U-joints. I will be using the through bolt style U-joint straps.

These measurements were taken with weight on wheels, meaning the car was not in the air on a lift. My experience with Certified Power Inc. and Ryan was a very good one – thus the reason for this article. I sent the measurements on a Monday night at 10pm via email. When I stopped by the facility the next day after work, the drive shaft was made, painted, and ready to go! That’s pretty good service in my book.  I did find a lateral scratch on the sealing surface of the transmission input yoke, but again excellent service prevailed. The yoke was replaced with no hassle and very quickly. I highly recommend these guys if you live in the St. Louis area.

transmission yoke
Also something to consider is a drive shaft loop. It’s a safety item… nuff said. (Thanks John!)
Make certain you driveshaft shop leaves enough room when building your driveshaft for installation. Slide the drive shaft forward about 1 inch, raise it up, and slide it back into position into the pinion yoke. Seen here also are the through bolt/strap style U-joint bolts for the 1350 series U-joints. Good stuff.
Make certain your driveshaft shop leaves enough room when building your driveshaft for installation. Slide the drive shaft forward about 1 inch while on the transmission output shaft, raise it up, and slide it back into position into the rear pinion yoke. Seen here also are the through bolt/strap style U-joint bolts for the 1350 series U-joints. Good stuff.
custom driveshaft installed
Now the custom drive shaft is installed (temporarily). On to the next project… This was a very easy item to engineer and should not be something that keeps you from upgrading a transmission or rear axle for better aftermarket pieces.

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