Would you suggest "total" rebuild on a 318 that has been sitting for like 15 years with the intake & heads off - apparently burnt exhaust valve(s) and previous owner was going to fix, but did not get around to it. Car has sat outside, hood down, in dry climate (well, as dry as canadian prairie could be) . . . being long time since seeing the car, so don't recall if the cylinders had rust in them, or on the cam . . . . thoughts ??