I have a 65 Mustang with the original 289 rebuilt and an aluminum radiator.
I was given the suggestion of removing the radiator cap which is rated at 16 pounds and replacing it with a 13 pound cap.
Is this a bad or good thing to do.
Any advise is appreciate.
If you are not having leaks I wouldn't. The higher pressure should allow more water to stay in the radiator, higher boiling point, and have better temperature management. Why would you want to change?