Where to get spring valve radiator cap?

[95Viper]

I have a 95 Viper. My original radiator cap has a drop type valve 16 lbs. The dealer replacement is 52079880aa which is a little different but is also a 16 lbs. drop type cap (the round valve at the botton within the rubber ring just hangs down when you hold it up versus a spring one that holds it against the ring).

I want a spring valve cap. Many have written about this fixing their coolant overflow problem. Where do I get one? Can I get one that looks like the original (showcar)?

Also...fyi to early Viper owners(I don't know what year this was changed). I called Dodge and ordered the 4 spring clamps (two different part numbers) that come on new Vipers to the 4 transitions from rubber to metal between the surrogate tank and the facia tank. There is an opportunity for a problem if these don't seal and it's also good enough for new Vipers so I'm doing it to mine.

 

[BruceW]

Roe Racing has them but there are not original replacements. They are sacrificial anode caps (i.e. they help reduce corrosion in the coolant system). They have a plug of zinc suspended from the bottom of the cap which attracts the corrosion process away from other parts of the engine. If you do get one, shorten the spring which holds the zinc to the cap so that it dangles in the coolant unimpeded. Without reducing its length it can catch on the inside of the tank and hold the vacuum valve open (which is what caused by tank to overflow).