72 Scamp front drums

Just a question for my knowledge bank. Does anyone know if and why all scamps came with a 10 in drum? I crashed my 73 duster and bought a donor 73 scamp and used its k, suspension and drums and noticed i had 9in before and 10 5x4 now . Also im going 8 3/4 with drum on the back will i be able to use my front drum system with a 383 bb with my stock master cylinder? I heard those front drums were used on many bb apps before minus the pattern. Input and suggestions welcome. Thanx