Early Chevrolet V-S's never had cam problems. Some where in the late 60's or 70's they quit using the "spit" holes in the the cam side of the connecting rods. The hole is still in most replacemant rod bearings; it's at the split line. Oil would flow to the cylinder wall and to the cam as the crank rotated. Today when I do a V-8 I will still file a groove in the rod cap so the oil will flow around the rod bolt and out on to the cam.
Another way is to widen the rod side play. In my racing engines I am over .025" which is probably more than needed for a street engine but I would still use a number around .015+" This will flow more oil on the cam. Yes we need the additive, more zinc, but flow will help.
The other culprit is spring pressure If you are not turning a lot of RPM you are probably using to much especially if you follow cam manufacturers specs. Get out an old motors manual and see what a 327 Corvette used for spring pressure and those engines easily reved to 6200. It will suprise you.
In all the years of racing GMC's with a flat tappet cam I have never hurt a lifter or a cam.
Good Luck
