Largest Tire Sizes for '66 Galaxie?

I have a '66 Galaxie that I would like to put a set of tires and rims on, and I'd like to put the largest wheels I can fit on.

Does anyone know the backspacing, etc. numbers for a '66? Thanks...

I just put on some 28 X 10.50 X 15 MT Sportsman Pros on my 66 500 XL.

I have them mounted on 15 x 8 Weld Rodlites with a 4 1/2 inch backspace.

They tuck under real nice and fill up the rear wells nice.

I will post some pics of this new set up in a few days here.
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This may sound stupid,BUT what would that tire size equate to in a radial?

I'm interested in putting a set of Lightning truck 18x9 rims on my Galaxie, and I'm just curious how they'll fit. They seem like they'll fit...

Nasal Goat... what year Galaxie do you have?

I am looking to put on some Astro Supremes 15X7s or 15X6s with 15X8s in the rear if possible. Do I need to get Reverse Offset?

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