You meant to say bypass system I think.
If "You" means Deve, Deve is referring to the full-flow filter system (original full-flow filter; or, his assembly on an original full-flow 261; or, an engine adapted for full-flow).
It is not clear which stovebolt engines/pumps HrL is referring to.
My good-condition stovebolt engines with stock oil pumps maintain oil pressure at idle (these are good-condition engines).
In particular, my 1960 261 with original full-flow filter canister (or, with a spin-on filter head) maintains oil pressure at idle on a warmed-up engine.
However, my worn-out 54 235 showed no pressure at idle - I read this as time for a rebuild (
done).
