what is different will they interchange? :confused: why
Thanks ed

66 3/4 with 350 3 on the tree tinted glass ps pb custom cab and a ks 10 locking rear 8 ft flt side
62k10 swb flt v8 4 sp 4x4
65 swb flt 6 w3 on the tree
72 vette
2 750 honda choppers

It won't work because the bolt hole pattern is different where the bumper bolts to the frame. You can make it work with a little cutting and welding. What you have to do is cut the HORNS (thats the very front of the frame that the bumper bolts to) off about 4 inchs back and get the same parts from a 63/66 doner truck and weld them on. Then a 60/61 will bolt right up. You might also need the spur brackets for the outer holes or just fill them with bumper bolts,which I dont reccomend for a daily driver but its okay on a show truck.
If you decide to do this,cut everything and bolt the new horns from the doner truck to the bumper then raise the bumper up with a jack to the correct height and have a helper align and hold the bumper in place until you get it tack welded. Remove the bolts and drop the bumper out of the way to finish the welding.
Hope this helps!!!!

The main difference is that the 60-62 trucks used a torsion bar front suspension and had a wider frame width than the 63-66, which used an A-arm front suspension with a narrower frame width. They will not interchange without a lot of modification. If it was me I'd be looking for the right year bumper for the right year truck. Just my .02 worth. Good Luck, and by the way welcome to the board from Louisiana.