i need some help with a hydraulic lifter problem. Recently installed a set of NEW hyd. lifters in my 56 Packard V8 engine. Did NOT use Packard lifters but used a 66 dodge 318 hyd lifter. Prior to installation i carefully measured the lifter from ALL external aspects and it matched an original Packard lifter perfently except for overall height which should have no significance. Even the valve lash is well with in specs of the factory manual.<P>SYMPTOMS: somewhere about 2200 rpm (50 mph) a negligable ticking sound (like a lifter) obtains off and on about every 1/4 mile or so and then leaves for about a 1/4 mile or so and repeats every 1/4 mile.<P>At 2700-3200 rpm (70-85 mph) the ticking is still slight but more pronounced and still on 1/4 to 1/2 mile intervals. Acceleration seems to aggrevate it.<P>This is not an objectionable ticking sound but nonetheless something i would like to solve.<P>I AM ALREADY WELL AWARE of the Packard oil pump problems and those mods have been made. These symptoms i describe are not results of the pump. The pump has been modified with plugged pressure relief valve , bushed shaft at both ends.<P>I am wondering if there is some internal deficiency in the lifters MoPar relative to Packard???