Breather tube as a return line

KitCarlson said
That line in my 66 is only about 1/4 OD. That would likely be too restrictive as a return. I did run a line from there to charcoal canister as part of evaporative emissions control, that works.

It is for a "great big" return regulator and or EFI. They are good enough for an orifice return like the factory used for vapor lock