I did the conversion on a 5HP B&S on a Gilson Rotary Hoe I got from the tip shop. I used a coil out of a 375 sprint off an old Rover mower. It was identical except for the mounting hole spacing. Luckily I have a mill in my workshop so a few minutes with a carbide burr to slot them a little and varoom, away it went.
Here is a list of the conversion coils.
There are three coils used on aluminum, single cylinder Briggs to convert from breaker point condenser to electronic as follows:
398593/395489/793281/793281/591420 are used on 2hp to 4hp engines, such as 60000, 80000, 90100, Quattro, and Classic
397358/697037/395490/395491 are used on 5hp engines such as 130000 series flat heads
398811/395492/398265 are used on 7hp to 16hp single cylinder engines, such as 170000, 190000, 280000, and 310000