Listed here you can buy drive chain by the link, please note that where the tooth of a sprocket enters the chain is a counted as a chain link.
You need to order an odd number of links, then with the joining link make an even number. e.g. 59 links + 1 joiner = 60 links
Listed is 35 ASA chain. 3/8″ pitch, inside width 4.68mm Roller Dia 5.08mm
420 chain 1/2″ x 1/4″ 1/2″ pitch , inside width 1/4″ Roller Dia 0.305″ (7.75mm)
428 chain 1/2″x 5/16″ pitch ,inside width 0.305″ Roller Dia 0.335″ (8.51mm)