The body of the starter is attached to the bell housing on the crankcase or transmission side by a flange with two or three bolts. Usually these are screwed into tapped holes but they are in close proximity to the transmission housing bolts and are often of the same size.
Read the full article at …… https://www.scottysretroworkshop.co.uk/2020/11/28/removing-refitting-starter-motors-on-classic-cars/
MGB tips mods and maintenance 