340 issue after camshaft change

Dave_J said
I think the OP has tightened the rocker down and the lifter piston has moved down past zero lash..... Then when the oil pressurizes the lifter it floats the valves.

With the intake manifold off I always look at the hydrolic lifter's top as I am turning the adjuster down, lifting the pushrod up and down as do this. If the top starts to compress you are at zero lash dry. Go 1/4 turn and LOCK that sucker down, do the next 15.

Fire it up and run the cam in at 2000 RPM for the 20 minutes. Then while still hot and lifters are pumped up, run the lash.

RustyRatRod said
Normal position for a hydraulic lifter is past zero lash, so I'm missing your point.

RRR, I HIGHLIGHTED my point above. ;) Click quote to expand.

I always set the lash at 'ZERO' plus a 1/4 turn for start, then after cam break in I do the running lash set and 1/2 turn. Messy but gets them pre set well.

My Eldy NHRA Magnum heads with Chevy rockers:
Eldy NHRA Mag 1.jpg