What rad cap should I use if I add a 1974

[jerry6]

coolant overflow/ recovery tank to the system , or is the same rad cap used for all systems ? Thanks .

 

[67Dart273]

Well, generally you want a coolant recovery cap. This is because they usually have a better gasket around the very top of the rad, and in the case of a "wrong" (non recovery) cap I had once, the rivet / lever / other out the top center won't leak.

You want an airtight seal around the very top of the radiator, to properly "slosh" coolant back and forth to / from the recovery.