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Anybody know a source for a 7lb radiator cap for my 70 BB with A/C? I am looking to lower the pressure in my cooling system and take it easy on the heater core. If you have ever changed one on these cars, you know what i am talking about. My car has the long brass expansion tank not the short aluminum one,.
Just looking for a stock looking metal cap.
7 psi cap is easy just about any parts store special order (probably) including Amazon. The problem is you won't find it as a look up for the car, So I would say you take your cap to a good store and take a risk and match up a cap that would work.
Now the down side of a 7psi you will lower your boil over and in a big block that's Not Hard in traffic.
I think you would be better off with a heater hose loop or shut off that can keep the pressure under the hood
Last edited by s carter; Dec 30, 2024 at 08:01 PM.
I did the same thing, for the same reason, 8lb cap. I think I just took my stock one into NAPA and they matched it up. My car runs pretty cold so no worries about not having enough pressure...
You really don't need to use a lower pressure cap. Just remove your current 15 lb. cap. Re - install the 15lb. cap to the first click. Your cooling system is now running with practically no pressure. Of course, you've also lowered the boiling point of the coolant.
7lb Radiator Cap
