from what I can see tractor pulling is now getting like all other motor sports the guy that gets 4th place is the guy with the lesser amount of money in his rig and did the best, 1st 2nd or 3rd are usually the huge dollar outfits and if you beat one with a junk old Belarus or something dont plan on going back to that pull.
It also depends if your in the "Group" or not as to what runs or don't at a lot of pulls. I was at a local pull the 1155 Massey that runs good and won its class is too new they told the guy to stay at home in the future, The David Brown that's the same age and cant hardly move the sled no problem pull all you want in its weight class, so go figure that one.
From the other comments I see about different things on here the big money and things that happen around will kill the sport in the end. pulling is supposed to be fun and for every body and budget from antique to 6 engine modified and that funs going out of the sport fast.