Backspacing sanity check

[68 SuperRam]

68 camaro - 12 bolt axle- disc brakes - 2 in drop springs / non rolled rear fender

from mounting surface - measured 4 1/2 inches to outter fender lip / and from surface to inner wheel well - measure 6 1/2 inches

looking to go with 17x8 on 245 45 17 with a 4 3/4 backspacing

Just looking for a sanity check to see if this is similar to what others have.

thanks