This was in western Missouri in the late 1960's...
4500 lb class- Wards,101 Massey,WD-45 Allis,77 Oliver,44 Massey
5500 lb class- 65 Massey,88 Oliver,M Farmall.D-17 Allis
7000 lb class- 560 Farmall,180 Allis,Super 90 Massey,1650 Oliver,G MM
9000 lb class- AC 190 XT,1100 Massey,4020 JD,806 IH
12000 lb class- AC 190 XT or D-21,806-856-1206-1256 Farmall.1130 Massey
15,000 lb class-D-21 Allis,1206 Farmall-1256 Farmall,5010 JD,Oliver 1950
I can remember in 1967-1968 when several times the AC-190 XTs's would win the 9000-12000-15000 classes..
Heres some pictures from the Rich Hill,MO pull in Aug 1969..Those were all friends of mine..
The 856 IH won the 12,000 lb class which is the only class he usually pulled...He rarely ever got beat in this class..
A bet was made that he couldnt out pull the D-21 AC in the 15,000 lb class..He was allowed to add some weights and all the people that could ride on the tractor..He made 3 full pulls with the 856 to beat the D-21..This was a walk on sled and it took a road grader to stop them...I was a sled rider and the bottom of the sled was very hot..
I later owned this 856 IH and did lots of pulling with it from 1974-1985..