im choosing a cam and dont know the max lift that the stock iron L98 heads can handle. if i want to go to something a little higher than the max lift of the heads, what machine work do i need to have done? can i get away with just a stiffer spring or will i need more? thanx

 

i am pretty sure the stock heads can handle up to about .500 lift.. after that you are going to need to have the valve guides trimmed or else they will wear themselves out

 

You should have the pressed in studs replaced w/ screw in studs.
My machine shop wouldnot promise the stock studs to take the lift w/ my cam,springs.
BD3

 

~.480 lift is pushing it for stock springs.

 

i am torn between the ZZ9 and LT4 cams. with 1.5 rocekers, the specs are:

ZZ9 212/216 dur@.050" .483/.520 lift 112' sep.

LT4 218/228 dur@.050" .492/.492 lift 12'sep

which of these do you guys reccomend and what mods need to be done to the stock heads. could i get away with LT4 if i just used a stiffer spring? if so, how stiff? thanx