Question:

Looking for bottom end parts on a 5hp Sheffield roto-tiller. Model number is 11943 or 12-5015. Year of tiller is 1975 and was manufactured by Outdoor Products.

Answers:

From Rose at Murray Canada thanks to a tip from Vern at Cummings Small Engine:
This is a General Power (Magna) Tiller (now MTD) sold by Noma/Canadiana nee Outdoor Products (now Murray) under their Sheffield Brand. Some parts may still be available through MTD. Rosie has a cross reference list to convert the old numbers to slightly less old GP numbers.