There is only one hole on the brake pedal arm. Just the ends are different (where the pushrod connects to the brake booster). It was a really easy swap. Don't worry about it, if you get parts from a donor truck, you only need the parts on the 'engine side' of the firewall, plus the pushrod that goes through the firewall.
I got my vacuum from the intake manifold. There was a spot (I don't know the size) where my tranny gets its vacuum from, I just put a tee on it and ran my booster off of that.
Now go out there and get busy...
