Well, the mid 70's ones were detuned a little from the late 60's/early 70's versions, but are still no slouch. You figure, they moved a car weighing slightly less than the Queen Mary pretty well, so in a lighter hot rod, they will do great. They do like to drink gas, but with the proper gears in the rear, even that won't be too bad.
Downside is that speed and dress up stuff is not as available as, let's say a sbc, and costly when it is, but the idea is to keep it pretty stock and just enjoy a torquey, smooth powerplant that you almost can't kill.
Looks like a good find you have there, I would use it in heartbeat.
Don