I have two '73s, and they are both strong tractors. Neither has run in a little while, but I got the 10 hp 110 running this weekend, and I forgot how much 10 hp really is. The varator is a tough system, even though you wouldn't believe its belt drive. The post-'71 tractors have the 1 inch diameter spindles, so it will take a little more wear and tear on thr front end.