1988 GMC TH400 slip yoke to 1973 driveline?

[dwmitchell61]

Well, I thought the universal joint spiders were the same size, to look at them. But that doesn't seem to be the case once I took the 1973 TH350 slip yoke off in hopes of putting the 1988 TH400 HD slip yoke on the driveline. The 1988spider is larger and won't fit into the driveline.

Is there a spider that is set up to connect the two? A mechanic friend of mine thought there is.

Or will we have to pay a machine shop to put a new end on the driveline and balance it?

[raceman6135]

Conversion universal joints are available.

Measure what you need, and check this chart to find out what 'series' each cross of the u-joint has:
http://www.driveshaftspecialist.com/...D%20Guide.html

Then, say for example you need 1310 series on one side and a 1350 series on the other side, scan down this page until you find it:
http://www.northerndrivetrain.com/ca...ionJoints.html

You will need a Spicer 5-460X. Take that part number to your favourite auto parts store and buy it, or their equivalent.