New Head

[geezer101]

Swapping springs and valves won't be a problem at all, but a cautionary tale must be told here. You can't go wrong with good quality valves. Don't ever just bolt a new head on out of the box without going over it thoroughly. Check the valve seats - make sure they pass a leakdown test, are all the valve collets and stem seals installed correctly etc. Is the machining solid (valve seats cut properly and matched with the valves). Really give it a good clean (you don't want any milling debris or worse - casting slag suddenly appearing and destroying the engine on first start up). I am apprehensive about using HD valve springs. Can't use them on hydraulic heads (not related to your install) but I tend to think they are rough on a stock valvetrain. The rockers get loaded up on their shafts and it will cause premature uneven wear eventually on both the shafts and inside of the rocker bushing/faces. Also I'd be concerned about the rocker arms showing signs of metal fatigue (we've all seen one or 2 break - it's rare but it does happen). I know the all mech G63B heads aren't super awesome for valvetrain lubrication but not sure what the 4G54 heads are like for getting oil through them.

[Lbuttsm91]

They are the standard size valves. Lord knows I wanted too but, i think the old lady woulda killed me for spending the money for that upgrade lol.