I remember being taught at college when i was an engineer apprentice in the merchant navy that an engine is most efficient when running at max torque revs – and most miles per gallon. The max torque on the MGB is at 2500rpm which is where i have stuck a green dot on the rev counter.
I have also added a red dot at 4000rpm as my max comfortable revs – although i don’t need a rev counter to tell me that – i can hear it!!! …..and feel it.