Re: 1961 Chevy Viking Front Clip Question
Since most of the earlier Skoolies were simply a flat firewall with a breadbox behind it, you can mount just about any front end you are willing to do the work for. Obviously one that is sized closely to what you started with will likely give you a head start, but as noted above, just about anything can be made to fit with enough work. Beyond starting with the width, check the wheel cutout location relative to the firewall as well.
And keep in mind that whatever you mount, doesn't necessarily have to go on the way it came off. It really wouldn't be difficult to weld all the pieces of any given front clip together...then hang the whole thing as a lift style, forward tilt front end. Could well be a lot less work in fact. Only one seam to have to line up!
Just thinkin' out loud.