"I could feel the bolt turning inside"

I have no idea what you mean by this. Please explain.

There are several areas of concern that could lock the motor up on the valvetrain:
1. rocker binding up on the stud
2. valve to piston interference
3. retainer contacting the top of the guide/valve seal
4. coil bind (spring stacking solid)

Nobody can tell you how much lift your motor can tolerate before any of these things take place because every motor is different. Nobody knows how much the decks have been cut, or how much the heads have been cut, or the valve seat position relative to the surface of the head or the actual compression height of the pistons or the length of the valves or the actual rocker arm ratio or the number of coils on the springs or the wire diameter of the springs or the clearance on the rockers at the studs or the clearance from the bottom of the retainer to the top of the valve guide. This is one area of engine building that you have to check yourself.