Re: Ford 4 bottom plow: too big for a 42 hp tract

2 bottom plows = 1 drawbar hp per 1" of plow - row crop
2-16 = 32 hp ~ Farmall M (33hp drawbar)
2-18 = 36 hp ~ Farmall Super M (39hp drawbar)

For 28" tires (utility tractors)add .25 hp per inch 2-12 = 30 hp ~ Ford 2600 (30hp drawbar)
2-14 = 35 hp ~ Ford 3600 (34hp drawbar)
2-16 = 40 hp ~ Ford 4600 (45hp drawbar)
2-18 = 45 hp ~ Ford 4600 (45hp drawbar)

3 bottom plows = 1.25 drawbar hp per 1" of plow - row crop
3-12 = 45 hp ~ Ford 5600 (52hp drawbar)
3-16 = 60 hp ~ Ford 6600 (58hp drawbar)
3-18 = 68 hp ~ Ford 7600 (67hp drawbar)

4 bottom plows = 1.5 drawbar hp per 1" of plow - row crop
4-14 = 84 hp ~ Ford 8600 (93hp drawbar)
4-16 = 96 hp ~ Ford 9600 (116hp drawbar)
4-18 = 108hp ~ Ford 9600 (116hp drawbar)

The chart I created was baised on clay soils and mounted plows for the 3 & 4 bottom models that tend to pull harder than trailing plows. I really don't have any experience with 5 or 6 bottom trailing plows but understand they tend to pull easier that mounted rollover plows. I've seen an old JD 830 pull a 5 bottom trailing plow - it had plenty of weight and could pull a house. I guess you could drop the hp requirement to 1hp per inch for trailing plows putting a 6-18 with in reach of the 9600. I'd stick to the chart however for rollovers.

I think we can all agree that the tractors specified are up to the challange.

When all is said and done the only way to really determine the best tractor / plow combination is to try it.

The chart I created was baised on clay soils and mounted plows for the 3 & 4 bottom models that tend to pull harder than trailing plows. I really don't have any experience with 5 or 6 bottom trailing plows but understand they tend to pull easier that mounted rollover plows. I've seen an old JD 830 pull a 5 bottom trailing plow - it had plenty of weight and could pull a house. I guess you could drop the hp requirement to 1hp per inch for trailing plows putting a 6-18 with in reach of the 9600. I'd stick to the chart however for rollovers.

I think we can all agree that the tractors specified are up to the challange.

When all is said and done the only way to really determine the best tractor / plow combination is to try it.

Just re looking the chart, if it is right there have been one heck of a lot of over worked tractors across North America. No one ever hooked onto less the 3 x 14 or 16 with a Farmall M. I can pull 2x12 in heavy clay with my Farmall 130.

Your chart says nothing about depth and depth will definately make a difference. That chart must have drawn up by a couple of guys who spent too long in a bar. I mean if that 9600 wouldn't pull 6 x 16, 8" deep in any farmable soil, I'd cut it up for scrap.