We need a master list. Unfortunately what I have isn’t marked. The new one came in no box. I didn’t install the one on my car, the used one says nothing on it.

A lot of guys put a ball bearing in the vacuum hose for the distributor. Looks stock but curved for performance and they don't want vacuum adv. Frankly this is the same here. Easy to install an orifice in the return line or block it. The real issue is running the carbs with no filter.

There are metal gas line filters with a return available. Not oem. Or run a standard filter.

Someone should get one manufactured as a real filter with a blocked return.

If you're not running the brass screen at the carb inlet fitting and running this separator with no screen you are running the risk of junking up the carbs especially idle/transition. All for the OEM look. Show car not driven fine, a driving car not so good.

the ones with no markings on the can are old repops .

The originals and later repops all have IN and OUT stamped in the can

and for a driver, a Wix #33041 listed for 71-73 chevy may work.
it is 4 5/8 long, and 2 1/16 od.
3/8" in and out with a 1/4" return.
i can't say if there is any restrictor or screen in the return because i don't have one to look at. i found this in my Wix master catalog.
just something else to ponder.

I bought a vapor separator from 521 Restorations last year. Supposedly his are suppose to be correct. Correct length of tubes inside. I haven't installed it yet. There is a thread on FBBO about this same subject.
https://www.forbbodiesonly.com/moparforum/threads/fuel-vapor-separator.236061/

Mine have the in and out. Nothing as to who made it or a part number.