You should definitely change cap to one that doesn't invite opening such a Lever-Vent.
I personally stay away from higher pressure caps, prefer 13bs.
Before tank install, 1970 383.
Post tank install, '69 318.
Waiting on my formed hoses, or the 2nd one now. Tough to find the right hoses, the last set I ordered were totally wrong so I still have these junkers on there and they really bother me, the top one is cracking.
Rad is from a '66 Monaco/Newport etc w/383 & AC, but has Dodge truck ears, I had it custom made from 2 radiators.
I'm was very lucky to finally get a radiator in it, nearly a 2 year search.
Stupidly, I tried to sell this radiator for a year after I had it rebuilt and found out it didn't fit. Had it been a B body rad, it would have sold in minutes, but been a C body rad, nobody wanted it, lucky me.
One day I realized I had a totally wasted big block truck rad that had the right ears and went and had them put on. The solution was staring at me in the face but I'd never realized it.
The truck had been without a rad for a whole year at this point, I was starting to despair at ever finding a proper rad for it.