It's not that bad I guess. Make sure you upgrade the idler pulley arms also if they have not been upgraded already, Pelican can supply you with new arms. They are a little pricey as I remember.
The only snag I ran into on the 72 is that two of the studs that hold the left timing chain cover on are not long enough to go all the way through the new aluminum style covers with the tensioner oil feed hole. You'll have to figure out what to do about this. Either leave them the way they are which might actually not be a bad idea (they are at the top and probably won't cause oil leaks) or do what I did, try to take both out, get one out, break the other, and say screw it and wait for engine drop time to fix the whole mess.
The reason the new covers are different is because the optional smog pump is installed on that cover and so two longer M8 studs are used where previously short M6 studs were in place on the early cars.
I did it in two separate weekends. If I had all the parts handy I could have done it in one.