340Help!!

That is extremly high, was this cam broke in at all? Was the timing set at all, after the first drive? You may be able to get away with a teardown, if your compression is down in one or more clyinders, Just swap cam, liffters, pushrods. Hopefully all is good with your valves, and other things money spent on.

No, .480 gross lift is pretty mild. Gross lift is what the valve sees. Net lift is lobe lift. If it had .480 net lift, that'd be pretty big.