[O.G.SS68]

IM new to the site so take it easy on me! My ? is an ive seen alot of talk on here but not a for sure answer. I want to run a 20" wheel on the rear of my 68 camaro i need to know if its possible an what size tire an back spacing! my car is not tubbed an im not to concerned with ride just the look an no rubbing. Thanks in advance for you input.