67 K10 U-joint problem. PLEASE HELP!

[kurts704]

Just finished lifting my 67 K10 stepper 4 inches and put in axles out of an 87 Blazer. Trying to mate the shafts to the axles. The yolks coming out of my axles are 3.75 inches, the ones on my old axles are 3.25. The old axles had u-bolts going through the yolk, the newer axles have staps with bolts. The u-joint ends are the right diameter, but are too short for the new yolk, only catches half the cap and there is nothing to hold them in from working outward. No clips. Do I need different caps? Different joints? Or will my old yolks fit in the new axles? Help! Everything else is done and I want to drive it!