Smallest Tire and Backspace Help

67 Barracuda currently has on the front, over KH disc:

14x6 Cragars, 4.125 backspace, with 215/70/R14.

Cragars are rusted, buying new tires.

I have another nice set, 14x6, a smaller backspace, 3.75 or 4, with 205/70/R14.

Measured the backspace last night and unfortunately going by memory. I only see 3.5 on summit, but these wheels are older, dated 03 I believe.

Both fit without issues, no rubbing. The 205 seem to be easier with the manual steering but they are close to baloney skins.

Unable to locate info on whether a 215 will fit without issues on the shorter backspaced wheel, anyone have this combo?

Also, I have one 5.5 wheel for a spare, what's the smallest tire you can mount on a 14x5.5 wheel?

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