Tire/Wheel fitment 64-65 El Camino

I'm trying to find out if a 235 60 15 on a 15X8" wheel with 4 1/4" backspacing will fit on the rear of a 64-65 El Camino..I have a Car Craft article showing that 15X8" with 4 1/2" backspacing will fit up to a 245 60 r15 on these models..Anyone know?
Thanks!