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Has anyone adjusted the valves on the newest 426 hemi crate motor from chrysler. Instructions say to adjust them to zero lash and then turn them in another 1 and 1/2 turns. Seems like alot to me.I would think that closer to zero would be better but this is my first hemi so maybe thats what they like. This thing only makes about 8 inches of vacuum at idle with the timing at 32degrees.The cam is stock with 278 duration so I think it should make alot more vacuum as my wedge with 284 cam made about 11 inches of vacuum (adjustable rockers 1/4 turn preload). Any ideas? Thanks , Charlie.



What's the lobe separation? This will dictate how much overlap the cam has. The smaller the number the more overlap and less vacuum you will have. I have a Comp Cam (FHO spec) hydraulic in my 472. I'm pulling 18" of vacuum. This cam has 274 duration and 113 degree lobe separation. I adjusted mine 1/2 turn past zero lash. I think 3/4 turn would be as far as I would go. Hemi valve gear is a little on the noisy side even when properly adjusted.