SBP disc brakes

I purchased a disc brake kit from pirate jacks, therefore my 69 barracuda with small bolt pattern 14 inch wheels. Currently I have a set of 14 inch steel rims 4 1/2 inch. I’m getting a little Rub from the caliber. I did a little grinding on the caliper to see if that would correct the issue but don’t wanna grind too much. I’m thinking about putting a small spacer between the hub and the wheel to see if that helps.
Any suggestions on where I might find a spacer for SBP hub?
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