Rev kit's are designed to keep the roller lifter in full contact with the cam. Roller lifters can skid on start up,creating flat spots,and eventually failure.
The rev kit also reduces the spring load at the valve.
I like mopar cam's. I've run some in my small block's and was always happy with em. Radical idle yes. BUT...mopar hasnt designed a NEW cam in years,so the old grinds have been outdated by new research. I would go with a company like comp or lunati,as they are on top of mopar .904 lifter design and build thier cams around the .904 lifter,not some chev junk.