How much "shake" at idle is acceptable?

262 duration/490 lift?
262 adv duration?
262 @ 050?
490 lift...........with 1.5 rockers?

It could not be a flat tappet cam with 262 adv duration & 1.5 rockers, even if the Mopar 904 lobes were used. It could be a roller cam, but such a short duration cam in a roller is unusual.
If it is a FT cam, then the specs provided are questionable. It may be that the cam is larger than thought & it just has a lumpy idle as a result, not necessarily a problem with the engine [ other than it may need further tuning ].