Paul, the Lev-R-Vent (red lever) is on both the 330 (non-vented) and 331 (vented) cap. The red lever merely allows the pressure to be relieved by lifting the lever (that way you can remove the radiator cap while the engine and coolant are still hot.
Keep in mind that the 330 cap is the same as the 230 except the 330 has the Lev-R-Vent. The 230 is the true stock replacement cap but both are non-vented.

Logic (possibly my flawed logic) would tell me that if a cap was spec'd for the radiator and the original application had a tube running to the ground with no chance for coolant recovery then that same cap wouldn't operate properly to allow coolant back into the radiator with a coolant recovery bottle.

Maybe I should call Stant and see what they say. I am really confused.

Paul, thanks for doing my homework!! I was afraid to comment, because I am sitting here thinking logically ( :lol: ) how can coolant be sucked back into the rad? Wouldnt that allow air to be sucked back in if I wasn't using an overflow jug? However, my experience is that when I hooked up the overflow jug to my regular replacement radiator cap, it worked just fine. That is, any coolant that goes into the jug when the radiator is hot does get sucked back into the radiator when the engine cools off. I have a stant cap, but I don't know which number. I do like the cap because it doesn't have any red lettering on it. Every repro cap I ever bought, including the Delco cap from the GM dealer... has leaked! Plus they are now made in India... no offense to Indians. :)

OK guys. Thanks for all the replies. I'll continue to use the 330 cap.

ttt