just recently noticed when motor is hot above 45psi / 2600rpm there is a slight flutter/buzz of the gauge . Not much maybe 2-5 psi . Autometer mechanical gauge with i think a -6 braided line
No problem cold . No problem at idle hot or on deceleration .
I noticed it , then oil and filter change as was due , still there .
I use RP 20/50 and use K&N HP filter .
I split the old filter , no jewellry .
I will pull the relief valve later this week and check its not sticky .
Its a World block , flat tappet cam
Can maybe try a different filter , maybe a Baldwin B2 ?
What are your thoughts ?

Tex