Front end swap

[jay'67]

Hey guys!!. I'm new here to this forum and new to the resotration world. Got my hands on a '67 GMC a few years back and have decided to fix it up. My first question is the front end. I've been told that a front crossmember off a early '80's truck will bolt right on, but found out that it is about 3/4" too wide to fit the original frame. I would like to convert to disk brakes. The 6 lug pattern does not bother me at all. Now I have new info. that a front end off a 70-72 will 'bolt right on'. I have thought about just getting the conversion kits for simplicity, but I have these front ends here in my yard. Is my info. source just full of bull, or will this fit as easily as he says. Ideally I would like it to just simply bolt right on to the frame as easily as the original comes off, but...... Can you give any advice.