Doing a brake job for a friend,need to know what's the max dia. the drum can be before it needs replacing. It's a 1962 Impala

usally it is casted into the iron of the drum

Harry,
Sometimes they get so rusty the numbers get unreadable.The farthest back my Wagner spec book goes is 1966 Impala,which is 11.060 .So if it is an 11 inch drum thats probably the spec.

As a general rule of thumb, the max dia is usually .060 over size. Some drums have 11.090 on them but I usually defer to the OEM specs if available.

bigger brakes? will impala front & rear brakes fit on a chevelle? explain!