Picked up a used master cylinder and booster, looking for info from m/c part number 5480348 (maybe 5460348).

thanks in advance

Probably 5460346
Casting#, not a part#.

1 1/8" bore, oval, dual bail. With pads for bleeders, but might not have them.

This is the info, accurate or not, I've got on it:
67-68 midsize GM disc/drum manual and power (depending on car). 67-72(?) Corvette disc/disc power brake only.

Machined pad on front can have a 2 letter code if a factory master, designating which pistons it had, and displacement capabilities... basically, which car it went on. The part# was different for each, and the code went with the part#.

Service replacements likely had no code, and many 67s didn't either. Corvette is stamped PG. I dont know all the others. They would be listed in a Chevy service manual only for that particular year. I think the 68 Camaro is 'WT' and the 67 is 'SA'.
In 1969 the disc/drum cars used a different cast (5468309). Chevelle was stamped 'BA'.

In 1970 I think they went to the rectangular 409 master for most cars.

thanks a ton!