The hood on the tractor says 770 Special Edition. It has a 12 hp B&S vertical engine but I'm pretty sure it's not what it came with hp wise. It runs great but the belts going to the 3 speed manual transmission were horrible and it had a bad engine oil leak. I removed the pulleys and belts, removed the engine and had the leak fixed. The engine is back on but the pictures I took of the belt tightener parts are no longer on my phone. I have all the parts but I need either some good pictures or drawings.
I don't know if this is a small or medium frame tractor. From what I've seen so far it looks the most like the description of maybe a 600?? it has a 3 speed transmission where you can go from high to low speed by changing the belt from the big to small pulley to the small to big pulley, I don't see any locking device to lock the rear wheels. It has plenty of power in the high range to pull a disk harrow with 280 lbs of weight on it but it's just too fast. I've been using it to prepare lawns for seeding. All I need is the diagram for the belt tightener that works with the clutch pedal. When you push on the clutch it releases the spring tension on the belt. When you release the clutch the spring tension engages the belt and it's transferred to the transmission.
I'm not interested in using it to mow unless I buy or make a pull behind mower that has it's own motor nor pushing or blowing snow.