And here is what the 1958 Truck shop manual says.
Caution: Do not install early 1957 mechanincal tappets in 1958
six cylinder truck engines. 1958 mechanical tappets have a annulus around the lifter body for passage of oil to the rocker shaft assembly as shown in Figure 15. The use of a mechanical tappet without the annulus would block the flow of oil to the rocker arm shaft assembly.
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So at least for the one engine that had this situation going for it, the blocked oil would be more inforce blowing past the lifters, bearings etc and on to the crank and then likely overwheming the oil control for the piston rings, (yeah you'd think the pressure regulator would offset it). Thus causing the extra oil consumption and the smoke. At least its a theory.
Last edited by Truckrolet; 07/13/2013 12:54 AM.
