[Captainfab]

I have installed a '67-'72 K series engine crossmember into a '62 K10 frame. I don't know where you measured, but there is not 1.5" difference in width in the area where the engine mount crossmember bolts in. The V8 engine mounts are basically the same from '63-'72 in the trucks except for the factory big block mounts from '68-'71. The '72 big block mounts are a 1 year only. Then there are the '73-'87 mounts. I would use everything from the '85 Burb. You may have to space the transfer case crossmember up some as the '61 K10 frame likely drops down a little more than the '85 Burb frame does.