How to convert a single field alt on to a double field alt

[Nacho-RT74]

Here you have the process to make the conversion, without need to buy a double field alt, keeping your existant one:

[Nacho-RT74]

this is teh brush setup provided on kits... to complete this conversion will need to use the NUMBER TWO isolator and brush... of course with screw and isolator washer showed on pic, on bottom

[Nacho-RT74]

some old school round back alts are already made like DOUBLE FIELD alts from factory. Mostly sure replacement alts to lates cars or upgrade done

[Nacho-RT74]

Some other roundback alts present this look on back, with a probably provision to the isolator and convert it on to dual field... however by the pic, I have doubts about clearance to fit the isolator, so COULD IT BE designed to fit a later brush without isolator, so still single field.

will need to be checked, however the alternator pic on reply above shows a square hole like this one... could it be the square provision is PERFECT for the isolator