Interesting suggestion to say the least . As to the issue of equalizsing the the purge line with the air pressure line I suspect the air pressure would be quite similar coming from the same crankcase cavities on the downstrokes.
why not just give it a try and feedback to us on your findings ….should you choose to “revert back”
One suggestion if you can…. use a clear line between the purge and check valve to see if the purged juices do flow out nicely to the tank via the check valve set up.
I have a nice 5.5 CD I may try this in the winter 2022 projects waiting in th basement ( 2x4hp and one CD 5.5 Johnson) .
Joining AOMCI has priviledges 🙂
