Looks to me like a V107 Cortina (71-72) which is supported by the series 70 muffler.
Your serial seems to indicate 1971, however I would expect to see more digits, specifically one or two more numbers at the front.
It is reasonably common for these first two numbers to be skewed, poorly stamped, or wraped around the crank case bolt housing, and therfore easy to miss.
