[68 Malibu 383]

Everything on a truck has a certain torque value. But on something like this there is good old common sense. The bolts are about 5/16 inches in nature so about 20 foot pounds would be a safe torque without overdoing it. Now most mechanics use a tried and true method of knowing when enough is enough. Just don't use a cheater bar on your wrench and you should be safe to go. If you were to use a torque wrench for everything you would never ever get anything put back together. Just use a good 6 point closed end wrench and you should be fine.

They were not anywhere near as tight as I thought they would be. One of my other cars has a bolt with a 12mm head and the spec is 85 ft/lbs so I thought this might be similar and wanted an actual number just in case. 20 is probably pretty close though.

 

[68 Malibu 383]

Fastener Tightening Specifications
Bolts - Center Bearing Support 59 lb ft
Bolts - Universal Joint Clamp Retaining (single and 2-piece propeller shaft-Front and Rear) 15 lb ft
Nut - Yoke Drive Shaft 123 lb ft

:-D