A "What is this thing" question

[Jeff in north Texas]

Ok, this is probably a stupid question, but I am just learning my way around these M37's.
There is a box-like thing located under the hood, on the firewall, on the drivers side. This is just above the steering column. A large conduit/cable goes into it from the generator.
What is this thing?
Thanks,
Jeff

[xm708]

that square thing you describe is a voltage reulator unlike newer cars it is external, also newer cars have alternators instaead of generators.

[Jeff in north Texas]

Thanks. I am familiar with the alt./gen. differences. I just never would have guessed that a voltage regulator would be that massive. I will have to take a peek inside it one of these days.
I assume that is I ever convert to an alternator, I could do away with this and use a more conventional volt. regulator?
Jeff

[Nickathome]

My truck had the original swapped with one that I think has an internal regulator(at least I hope thats what it is), so in mine there is no lunch box under the hood.