560 vs 660 differential housings

I took this picture the other day as I got a flat and used the opportunity to put one of my wheel weights on the inside. Not looking forward to doing the other side

The International 560 and 660 differences are few. The 660 radiator is three inches higher and that affects the "dog legs". Extension are spot welded to the bottom of the 560 legs. The fan moves up to 6 blades from 5. A cast iron spacer is fitted below the front of the grill. From the axle housings to the rear tires, everything is different. I have just listed all the differences with the exception of the badges.

The engines are identical and that includes the pump and injectors. The 660 is adjusted for 600 more rpm.

Are you saying that those 660 axle housings, axles and planetaries will bolt up to a 560 transmission housing? That would be interesting.

Lets assume that you have a M-SM and you want to go slow, real slow. You could put in the M-SM low-low first gear kit, one of the 560-660 differential sets (I forget which one and I not going to look it up unless requested), and the planetary axle. The 660 also had an optional tire size that may give a further reduction.

You could also modify a SMTA w/TA and later tractors (low-low kit is not available) for a substantial reduction. In that case you would use the F560 first gear.

I am not up to pouring thru the parts books and doing the math at this moment. I will say that I built a SMTA with F560 differential gears, F560 first gear, good TA, and 15.5x38 tires. It's a creeper in first gear low range. Top governed speed in direct is 11 mph.