Hydraulic switch unit - S3 onto S2

Has anyone used a S3 type hydraulic brake switch unit On a S1/2 ?
This is for a mate who gotta winter S2 project & With the S1/2 being of a larger diameter
he’s asking can we use the hydraulic brake setup off his 83 Spanish LI ?
Has anyone did this ! as We believe it’ll need machining or reaming out to fit so which is the best way forward...
Cheers
This is for a mate who gotta winter S2 project & With the S1/2 being of a larger diameter
he’s asking can we use the hydraulic brake setup off his 83 Spanish LI ?
Has anyone did this ! as We believe it’ll need machining or reaming out to fit so which is the best way forward...
Cheers