Quote: The end play is set at .015thou. I understand the timming cover may flex a little if the button runs against it. Correct me if I am wrong but dosnt the turning of the dizzy/oil pump drive force the cam to the back of the block, I thought this is what the torrington on the back of the timmig gear set was for?
Tim
.015" end play on the cam is a bit too much. I would drop that down to about .005-.006". Two things force a stock flat tappet cam backwards on a big block Chrysler. One the position of the distributor drive and the helix on the cam/distributor drive gear and the other is the taper on the lobes. Roller cams are ground flat so the only thing driving it back is the first point.
However, acceleration/deceleration will cause the cam to walk. Also, if your lifter bores are not straight or out of alignment, this could cause the cam to walk forward.
I would side on the opinion that thicker oil can wear out the gear prematurely. It takes more force to spin the pump. Also, if there are any burrs or imperfections on the cam drive gear it will wear the gear early. Usually the first gear wears out faster until the cam gear takes a "set".
