RE: twin drive belts
I found a belt part number A-51K (the Patent number is not important) listed on several tractor parts companies shown below; it may be the same belt, you need check the size to be sure.
Tractor Supply Company
Huskee Vee belt
Manufacturers Number: A51K
V-Belt; 1/2 x 53 in Size; Rubber Material; Blue Color
Kevlar Blue V-Belt (1/2 X 53" )"
Item #: A-A51K Quantity in package = 1 o.c. length: 1/2 X 53"
top width: 1/2" depth: 5/16"
If you have a contact in the US surely a NAPA store can get it for you also.
As it is a tractor part also you may find it at a tractor dealer in Venezuela, John Deere, Case, Massey Ferguson The important thing is the size, 1/2 inch wide, 53" outer circumference, 5/16 inch deep, be sure these sizes are the same on your old belt.