New to site, new to Mopar overheating issues

Nope. Same could be said about you. I dont want a half assed fix. Do you know what his pulley ratio is? I can tell you the pulleys are 67-69. Did 68-69 318 and 340 use the same pulley ratio for non A/C ??? I am betting yes. As such it needs an 8 vane pump.

And you are comparing pulley ratios on a 73 318 and 340 to what exactly??? The pulleys on his car? Those are not 73 pulleys. Most likely a different ratio altogether. I told you what year to year I believe they are. Why dont you pull up that section in a 68 or 69 FSM and see if the 68-69 318 and 340 non A/C pulley ratios are the same or different. If they are the same, and I am betting they are then he isnt underdriving ****. Unless hes using an A/C style 6 vane pump.

Your the one comparing apples to oranges. Not me. What's the pulley ratio on a 68-69 318 and a 68-69 340 non A/C. That's what we are comparing. Not what's in the 1973 FSM which has no relavance to 1968-1969 pulleys which what he has.

Oh and while we are at it sizing the pump to fit the correct pulley ratio it belongs with isnt underdriving anything. Its sizing it up correctly. Add in a recored radiator with an extra row of tubes if a desert cooler core will fit the tanks. No overheating issues.