Yes, the engine and transmission you plan to use does matter. Without that useful info it would be anyone's guess. Another useful piece of info would be whether you plan to have 6 lug or 5 lug wheels.

I'm using a 3.07 out of a '59 GMC in my '56 with a 350/400. Nice ratio if you want 6 lugs.

To answer your question about width, there is some leeway. The offset of the wheels used can compensate for some variations.

I'm sure others will chime in soon with what they've used.

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.