I think if your engine is original,it'll have the "short" water pump,so you will probably need to get the "longer" pump in order to move the alternator to the passenger side ,and get the belts to align...
I think in '73 GM decided to go with the longer water pump when they moved the altenator to the other side..
I recall some having troubles getting the right water pumps,when I sold rebuilts the A-1 Cardone ones came with a spacer--there were two different long pumps,one had the threaded tab for the P/S pump in a lower position and they decided to make one pump fit both applications..if you went with a new pump,or some other brand,you had to be sure to get the right one for your application,using the casting numbers off the original was the best way to determine that..
Some early 70's GM's still used that round can P/S pump--have you tried mounting it to your brackets ?...the "canned ham" ones came around the same time...it might fit and work,check to see the belt lines up,if it does fit the brackets..
Your engine is a car engine ,having a "C" prefix--a truck code begins with a "T"...looed on this site on google and found "CNO" comes up to be a 1970 350 ..
Chevy Camaro Engine Suffix Codes