1970 C60 brake expectations

[Nobighurry]

Hey guys - need some input. I've got a 70 c60 ex fire truck. Low mileage flatbed now. I just spent $1000 getting the brakes redone - yes I feel ripped, but I just wanted to make sure they were right for this size truck. Here's the thing, the brakes aren't impressive at all. I mean, they seem to work ok, but just feel - like I said, not impressive. I couldn't imagine these trucks hauling tons of weight, towing tons as well with brakes like this. I mean, I don't expect 2017 caliber stopping, but something better than what I'm getting. The wheel cylinders were replaced and the master cylinder was done just before I bought the truck in the spring. I had a commercial truck service center do the work.
Just looking to see if my expectations are just too high. I appreciate any thoughts and input.