[schade]

your probably gonna have to do a little grinding on the head to get the cams to fit properly ... with stage 1's and sometimes 2's you don't usually have to .. but almost all the time with stages 3's you gotta do some head work to get them to fit

and yes you can change out the valve springs while the head is on the car by hooking up an air line through the spark plug hole and pressurising the chamber ... otherwise you'd have to pull the head to avoid dropping a valve into the block