I can double check my notes at the shop, we have 3 '69 Camaros/F-birds with 18's on the back w/ no tubs. Generally, a 18x9.5" wheel will fit with a 5.5" backspace on a stock 10 or 12-bolt.
18x8 front (4.875" b/s) 245/45
18X10 rear (5.625" b/s) 275/40
No tubs or modifications...
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