My buddy built a 440- large hydraulic cam, bit of headwork, and 9.5 to 1 compression. Stamped HD rockers.
He drove it for a few months, and when I got in the car I could have sworn the car had solid lifters when I went for a drive.
At idle, quiet and smooth. Cruising, ticking and smooth. It was weird! I looked under the covers and couldn't see anything. NOT Rhoads lifters BTW!!!
Fast forward one year.
He builds ANOTHER car. 500ci stroker this time. Stealth heads, .500"ish lift hydraulic, MP HD stamped rockers. Comp Cam and lifters.
He phones me and tells me his new engine does EXACTLY the same thing!
It idles quiet and smooth, but as the revs come up cruising it sounds like a solid cammed car.
The ONLY thing that is connecting the two engines in any way that MIGHT have anything to do with it is BOTH engines have high PRESSURE pumps, not high volume.
I've never ran a high PRESSURE pump on a big block, usually high volume pumps, so I have to ask- is a high PRESSURE pump likely to have any possibility of making a quiet hydraulic cammed engine sound like a mechanical cam at cruising speeds???
It's just a higher relief pressure....