The tractor skid is basedon the IH world wide series tractor fitted with the HD cast front axle ( 454 / 574 tractors)
If it is a 3 cyl diesel engine it is a 2400 if 4 cyl it is a 2500 model they were made from 1970 to 1978 then were based on the 84 series tractots ( 484 to 884 tractors built 1978 to 1982)
Do you require a service manual, i sell PDF copies of the genuine IH manuals, send me a PM with your e mail address.