Redmatch,
What was the other wheel doing? (Please anyone correct me if Im wrong!!!)
If you do a burn out, with an open diff, the one wheel spinning is actually going twice as fast as your speedo says. If both wheels were spinning evenly, (such as driving down a strait road), they spin at the indicated speed.
Now. you had both wheels off the ground, and spun one. When I have done this in the past, the other wheel actually goes backwards, and the drive shaft does not spin (open diff) .
If you have a positrac or similar, there is still a degree of slip, meaning the wheel you are tuning may do one full rotation, but the other doesnt quite get around a full rotation. this means that the driveshaft also does not give its full number of rotations.
Given that you had your son turn one wheel while you were watching the drivshaft, Im guessing you dont really know what the other wheel was doing.
Get onother person to turn the other wheel at the same time as your son, while you count the driveshapt rotations It doesn;t matter if they arrive at one rotation at slightly different times, the effect on the driveshaft will be the same.

Hope this makes sense!!

 

Good point guys. No, I did not notice which way the other tire was turning, I did notice if I jacked up one side I couldn't turn the tire. I will try that tomorrow. I hope I get a different ratio, I don't know what else it could be. Thanks

ps The book says traction lock, is that posi?

 

Yeah, posi is actually a chevy term (positraction).

 

My 73 is factory equipped with a 14 inch tire and wheel, 4 speed with 1 to 1 final drive ratio and 3.25 gears. At 70 MPH my tach is showing 3300 RPM. Tires are BFG . Hope this helps. Dean

[IMG]local://upfiles/26494/E5CDE9F0111B4B0E9C031FD2ED1E3008.jpg[/IMG]

 

Have you checked your clutch assembly/linkage? Could be that you are getting slippage.