Guys... just wondering... if my memory serves from my garage days as a kid, if your car has hydraulic lifters then the idle can be lower as the
oil is pumped up thru the valve push rods. If you have solid lifters then there is no
oil delivery thru the valve rods and so you have to have a higher or sufficient RPM at idle to lubricate the upper end.
Is my understanding of this correct and still valid or is this memory a 1960's wives tale? As you get on in years... some things get cloudy. ;-)