Curious question. In my two 327`s , one has a high VOL.pump that reads 80 psi on the test at road speed and drops to 30 psi at idle.
The other has a low VOL. pump and will reads 30-35 psi at road speed and drops to 12-14 psi at idle. Both after warm up.
The 235 I just had rebuilt will run today. I can check it.

~ BD.
"You won't find me in an old folks home" Pioneer Florida Cracker
1958 Apache Stepside
1958 Apache 1/2 ton Panel
1959 Apache 1/2 ton Panel