Can a head set up for max .520 lift w/flat tappet hyd cam be used with a hyd roller at same lift safely. If not, why?

 

Different spring pressures are needed. Flat tappets run anywhere from 95-115 on the seat and up to 280 open, hyd roller needs 120-150 seat and 295-330 open depending on ramp rates. Spring setups for mechanical flat tappet and hyd roller are similar.

 

roller cams, allow higher ramp rates,
so, in general, if the cam design takes advantage
of the benefits of the roller,
higher spring pressures will be needed.

every cam has recommended spring pressure
and rpm limit

 

If it's a billet cam then higher spring pressure can be used. If it's a cast cam, stick to the recommended spring pressures. Too high an open spring pressure on a cast cam can break it.

Roller cams always want higher spring pressure than a flat tappet cam. If your springs are designed for a flat tappet and you're switching to a roller, you should be changes valve springs.

 

Thanks guys