if you build ls vtec do it right don't use gsr parts b/c the rods are shorter tha ls rods the pistons don't have enough compression to do anything for you and if u use a gsr crank shaft you are destroking the motor making less low end power and high end power as well.

here is what to do to build a safe and fast ls vtec
1 eagle rods
2 11:1 comp pistons
3 block girdle to reduce vibrations(gsr and type r blocks have them)
4 p72 gsr head for higher comp. ratios(i have one for sale)
5 either a b16 or gsr tranny(ls gears are too long to do anythin except boost with)