Glad you like the info. Sonny, it looks like your front loop is still original, so just the rear portion of it needs changing. I measured the length of the rod. I hope you can follow the way I measured this, because I can't measure through the 2 holes with it assembled like it is, unless I had a tape with no end on it. Anyway, from the front, at the edge of the metal that comes down from the square hole, the narrow edge of the piece in my pic, that's just after the loop at the front, along the rod to the very rear of it looking down through the hole on the mower, is 32 3/8 inches. This has to be pretty precise so it will adjust right, and the bar is 90 degrees out from the tractor, actually the IH manual says to have just a slight lead at the outer end of the bar when it's down and mowing.
Putting the mower on the Cub with the rod the original way is not hard when you know how. I put everything on the tractor except the front rod, and the pitman. It's easier with 2 people too. You need the lift chain in place too. Lift the mower up off the ground slightly, the other person should hold the outer end of the bar, so it doesn't swing around on it's own. Then put the rear of the rod up through the hole in the mower, and lay it down in place, then you have to move the outer end of the mower bar one way, while you put the end of the square shaft in the square hole, then move the bar the direction so the square shaft goes into the hole, It's not as hard as it sounds. Tighten the bolt at the square hole. Then put the pitman on. I put it on last because it doesn't bend much. Then check the alignment, the bar should be 90 degrees out from the tractor. Pull back on the outer end of the bar and look down the bar to the pitman, I like mine so the metal the pitman bearing is on is straight, not bent forward or back between the bearing and the wood. That's where it will be running when you are mowing. Adjust the position by moving the square shaft in or out of the hole. Check the bolt there some too, mine gets loose after some use. You don't want the piece falling out, you will bend the rod probably. We've had this same Cub and mower for 41 years. I just worked on the bar again this year, replacing some parts, so it cuts better.