Universal joints:
Swapping a 14 bolt in place of a 10 bolt can get a little tricky to some because of the possible need for a conversion U joint. All 14 bolts that i have seen, both SF and FF, use a Spicer 1350 U joint. With this said, GM doesn't commonly use a Spicer 1350 joint on 1/2 ton trucks, most commonly they use a Saginaw S44 joint. I have however seen Spicer 1310 joints, and the occasional Spicer 1330.
Obtaining a positive ID on the joint isn't hard at all, just pull the joint, and measure it. If by chance you have stock U joints, you'll have to take a torch, and heat the caps up until all of the nylon melts out of the driveshaft and oozes out of the holes. Rather than using a retainer clip like the replacement joints do, GM uses an injected nylon retainer. Now that you've got the U joint out, you can measure it and see what it actually is. Here are the specs of the 4 above joints:
Saginaw S44: Cap diameter- 1.125", Lockup - Internal (clips inside the yoke) 2.556"
Spicer 1310: Cap diameter - 1.063", Lockup - External (clips outside the yoke) 3.219"
Spicer 1330: Cap diameter - 1.063", lockup - External 3.622"
Spicer 1350: Cap diameter - 1.188", Lockup - External 3.622"
Now that you have determined the stock U joint, you can find which conversion joint you need:
Straight Size Joints:
S44 Neapco PN: 2-3011
1310 Neapco PN: 1-0153
1330 Neapco PN: 2-4800
1350 Neapco PN: 2-0053
Conversion Joints:
S44 to 1350 is Neapco PN 2-1153
1310 to 1350 is Neapco PN 3-3140
1330 to 1350 is Neapco PN 2-3050
If by chance you have any other combination, which would be an extremely rare case, you can look up the joints by size here:
http://www.aawheel.com/SiteResources...oUniversal.pdf Dimensional listings start on page 260.
