I have been using a 16 lb. psi radiator cap in my '70 Duster 340. However, I just stumbled across some info. from AMD that listed a 14 lb. psi cap for this car.
So, what are you fellows using in your '70 340 engines and which is the factory correct cap we all should be using?
2# will raise the boiling point 6°. No biggie. I had a old leaky cap on my Swinger and it would overheat with the a/c on. I put a new 16# cap on and now have a heater core leak. Yep,it can happen that way.