Disc Brake Caliper ID

[2buck]

Is there an easy way to ID a metric GM Caliper (2-1/2" bore) from the regular caliper with the 2-15/16" bore? Do both use the same size brake pads?
I am running a LoBuck Disc Brake Kit that was bought in the early 80's.
I can pull the caliper and physically measure the unit but is there an easier way?
I was told to use only a 15/16" bore master cylinder with the Metric Caliper(s).
The 1" bore master cylinder should be used with the 2-15/16" bore units. All this info is without a power booster.
Thanks for your assistance!

[enjenjo]

Measure the distance between caliper mounting bolts. As I recall, the metric caliper is about 6", and the big caliper is about 7"

[Dave]

Is there an easy way to ID a metric GM Caliper (2-1/2" bore) from the regular caliper with the 2-15/16" bore? Do both use the same size brake pads?
I am running a LoBuck Disc Brake Kit that was bought in the early 80's.
I can pull the caliper and physically measure the unit but is there an easier way?
I was told to use only a 15/16" bore master cylinder with the Metric Caliper(s).
The 1" bore master cylinder should be used with the 2-15/16" bore units. All this info is without a power booster.
Thanks for your assistance!

What are the casting numbers on the calipers. They can be looked up that way too.
Ive never heard that about the m/c bore .
Dave