Mine had belts; at least three, maybe four. One for the blades; and either two or three to drive the 2-speed front wheel. That was in addition to the chain.
Cut height was controlled by spacers under the blades.
The thing was virtually indestructible. Virtually indestructible, but not actually indestructible because I did manage to burn up the worm gearbox that turns horizontal belt drive to vertical chain drive. I did rebuild the engine once but that was more out of boredom than it needing rebuilt. Nothing else on it ever wore out after 11 years and an estimated 165 acres mowed.
We fawn over 'fabricated deck' mowers. With this one, EVERYTHING is fabricated.
This is the same as mine, except mine had a crank/ratchet starter.