in our tractor clubs we have 6 weight classes. up to 12,000 lbs and 250 ft for a full pull. we also have an old ford flathead and an old 6 cyl. green diamond ihc trucks that pull for the fun of it. trucks have the regular old style dual wheel tires on them. they pull pretty dam good usually get about 3/4 the way down the track. the chain is hooked quite high on the truck so they both run out of power, not spin out. so many factors to consider.... plus the trucks are reving way faster than our antique tractors . plus the sled has gears and is used according to the tractor class. it is a fun pull so I never did find out what the sled is set at.
so with your questions the farmall and 8n ford would be in the bantom or 1st class depending on weight. don't know if your referring to antique vehicles or new ones. just as a guesstamite I would say an old 1/2 ton 2 wheel drive probably out pull them. I will look into this this summer once I get pulling.
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