I have acquired a 1981 John Deere 317 tractor I need to know the length of the draft arms that hook the mower to the tractor frame they are 2 pieces of 3/8 flat bar with 3 holes and 2 bends dealer cannot help (obsolete)part.they were gone on the mower when I bought it. I need total length and hole spacing to make them.One end of them hooks on 3/4 shaft at the back of the mower deck thank you.