well i know that it is bad to rev a LS/vtec motor higher than 8k because of r/s ratio (unless that is taken care of) but will just an LS head be able to rev that high with no problem with a built head (cams, valvetrain,etc.)??

 

Its not the head on the LS you have to worry about its the bottom end. LS/VTEC shouldnt be revved much past 7000 becuase thats the redline on the stock LS bottom end.

 

8K + stock LS bottom end = very bad things. You need to build your LS/VTEC to safely rev to 8k.

 

Yup if you want to take your ls to that 8k rpm you need to build it real nice to run it safely.