Power brakes

[72kat]

I have a 72 c10 with 350 and 350 turbo. Was fixing it up with a buddy who was the brains of the operation. He unexpectedly passed away a month ago.
I seriously thought about selling the truck off as its a huge reminder. But recently, I thought damnit I'm going to finish it for him.

We put a edelbrock aluminum intake on it and a Holy 670 cfm street avenger carb. The truck has regular brakes (disks in front, drums in rear). We were going to upgrade the brakes to power brakes, but I'm not sure where to connect the vacuum line from the canister. Somewhere on the carb? Somewhere on the manifold?

Any help appreciated.
Thanks.