1966 valiant rim width with spacers

I agree with the above, I was being conservative in my measurements but I didn’t want to get trapped. I had also measured to the leaf strap in case it interferes with the wheel. That ate up about 1/4” or more, I had found some 7” wheels with 6” backspace but again yes tight, I can trim the fender lip for another 1/2 inch. And stretch tires a bit.
I guess in the end the goal obviously is to be as wide as I can for feel and wheel options.

as for the bolt pattern I have already swapped the front to 4.5 with disc brakes so no going backwards! Maybe later swap the rear end but not this year.