Thanks. I was looking at the Isky Tool Room series after Mike Jones cams recommended them on another forum, but the 9935 is too light according to the cam grinders. At 245# seat and 490# rate, that's only 559# at 0.640". The 9985 appears to be the only one in their catalog at 1.560" diameter that comes close with 245# seat and 600# rate, but that's 629# at 0.640, a little shy of the recommended 640#. I don't know how crucial 10# open is, but I guess that's a good question for the cam grinder.