Eddie, as I mentioned, it was only necessary to have the cam lobes ground with a progressive degree of advance from the #1 cylinder down the line to the #6 in these 250-292 engines, and that was when large or huge lift roller cams were used. That purpose was for one reason and one reason only. To achieve the extreme valve lifts used in these engines by Jim, the base circles of the cam lobes had to be reduced so much, that this weakened the cams to the point that they twisted the entire shaft just by adjusting the valves. You wouldn't think that would be possible with a billet roller cam, but when the base circle and cam barrel is ground to less than .875 diameter(necessary to obtain near 1" of valve lift), it would happen every time. He found that after the spring pressure loads(near 1000 lbs. of open pressure) were applied to the camshaft, that the #6 cylinder was retarded as much as 5° from the #1 cylinder. He found that each of the cylinders in between shared a proportionally and consistent degrading of cam timing as well. He simply had the cams ground with a predetermined amount of advance on each lobe to compensate for the twisting of the cam due to spring pressure loads, nothing else. You will never obtain that much spring pressure in a flat tappet cam to have to do that(you will wipe the lobes right off) or most any roller cams up to .800 lift or more as long as the base cirlce on the lobes/cam barrel is .900 diameter or larger.
