Besides being a GK cam, what are you trying to figure out? 300 is duration but not sure at what lifter rise.
You can measure the lift yourself.

All I know is I never saw or heard of a GK cam being anything but a great cam choice back in the 70’s.

I sold tons of them and used them in many of my customer’s engines and in mine.

The most popular cam I sold for a B/RB was the A5H-288-B. Blew the doors off the Racer Brown SSH-25 and 44’’s.