how much of a differance will 1.6 rockers make on my stock lo3 heads? will i have to replace the stocl valvesprings? also is rhere a formula to calculate lift diff?

 

not much to none, the stock springs ought to be wore out by now anyway, bt as far as lift and all they should be fine. really need to know what cam you're running as well as what heads.

 

stock heads and cam from a 89 rs l03

 

The change in ratio will make very little difference.

Getting the stock rubber rockers out of there and putting something in that makes the valves follow the cam, may make alot of difference, depending on just how crappy and worn-out your particular rockers are.