1968? Simplicity Mower Deck Belt?

Question:Does anyone know what size belt a 1968 Simplicity Landlord 10 HP stock mower deck takes?

Answers:
If I didn't know and couldn't find out I would take a piece of rope and run it like the belt would run than measure it or compare it to a new belt. I get my belts from Ace hardware, they have belts in 1 inch incraments. They let me try belts and exchange them if they don't fit. Belt width is also important. Most are 1/2 inch.