Need advice with lowering blocks

[D-n-Tyke]

Reinstalling 1 loweing blocks and am getting confused which way the wedge poinys. I installed them with the fat part of the wedge forward, pointing the pinon up more. However I am thinking it is pointing to far up now. When I put a angle gauge on the pinon and zero it out, then put the gauge on the slip yoke of the 2 piece shaft I get 7+ degrees. Should these both be the same? Do I have the blocks in backwards?

[1970 CST Short Wide]

You need to turn them around and re measure the angle. I think you’ll find it’s much better

[HO455]

Unfortunately it's not as easy as that. With a two piece drive line you have to take both shafts, the pinon angle, and the centerline of the engine into account.

You can't get an accurate measurements of the pinion angle from the cast iron housing. You will need to find a way to measure off of on of the machined part of the yoke. In the past I have removed the circlip from the U-joint and used a socket for a spacer by sitting one end on the end of the U-joint bearing and set the angle guage on the socket. Like in the photo.

Here is some information on the process. If Spicer's information doesn't make sense there are lots of other videos out there.

https://spicerparts.com/videos/measu...erating-angles

https://spicerparts.com/calculators/...gle-calculator

Here is a link to how I measured my angles. Scroll to post 348.

http://67-72chevytrucks.com/vboard/s...698377&page=14.

Keep the questions and photos coming we will get you through this project. Once you get some accurate measurements we will be able to help with how you need to install the blocks.

[BROWN 70]

great info, ho 455. Brown 70

[D-n-Tyke]

Well got frustrated and just ended up goiing out and spun them around. I goy numbers that I took to be much better numbers. O on the rear end and .2 on the csnter slip joint.

Thanks HO455. Looks like I have some more to look to do. I will review the links you posted and get back with some numbers.

[Richard]

The operating angle of the joint is what matters. Not the parts. The parts create the operating angle. If operating angle is over 3 degrees it is not the end of the world. Just less life. For a non daily driver there is no concern for more angle. Even for a daily the actual facts about ujoint life may be surprising. Check out the tech articles at Tom Woods driveshafts to see what I am saying. There are three joints in a two piece drive shaft. One should be at 1 degree or less as there is nothing to cancel it out. Typically at the transmission. The other two should be within 1-2 degrees. The pinion should have the +1-2 degrees to allow for load when driving. It is simple but can be hard to understand. Again the working angle.