Running a hydraulic lifter on a solid lifter cam will increase the duration and lift slightly, as the valve will start to lift while the lifter is on the clearance ramp, and will not close fully until after the lifter leaves the ramp on the heel of the lobe. Acceleration/deceleration ramps on hydraulic cams are there, just much shorter and steeper than solid lifter cams. One of the hottest street engines I ever built was in a 55 Chevy 265 with a 56 Corvette "078" solid lifter shaft with hydraulic lifters on it- - - -way before I knew any better than to do something like that!
Jerry

Last edited by Hotrod Lincoln; 08/19/2014 2:52 PM.
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