27 or 28 tall 4.5 wide, I will be running 28 by 4.5 Hoosier on my 70 dart, 28 take a little body work so maybe try a used pair out 1st. You have tall tires in back id suggest Hoosier 29.5 by 11.5 w..
The actual measurements are slightly larger @ 30.6 by 13.5 tread