I had the valve covers off while the motor was running and was able to vary and or eliminate the noise by applying pressure on the rockers and making rocker adjustments. We thought we had eliminated the problem but it was just what happens when the motor warms up. I don't see why the pushrod length would be different between solid and hydraulic. The length requirement should be a function of the cam lift and the rocker geometry. So here are my variables: Cam - unknown (was told purple hemi-grind cam installed 15 years ago so I assumed .284/.484), Lifters - was solid (none compress, no wear showing) now have hydraulic, Rockers - were the stock non-adjustable (all appeared to have lash, since they were sloppy with both valves closed, which I assumed was due to wear/age) now have 1.7 roller rockers. I think I should get a new cam since I don't know what I have. I would like to keep the 1.7 rockers so I don't have to spend more to replace (although I would replace them if I deemed necessary). I attached a word document of my heads in a previous post in this thread and also my other components. I have 3.23 gears with a 4 speed. Could someone give me some suggestions on cam solid/hydraulic and lift/duration. I just want to minimize my effort (lazy) and cost while optimizing my setup for street. I'm not too worried about the noise because, although I don't yet understand why it changes, I'm certain of where it's from. Thanks to anyone who actually read through all this.