Yes your setup will work. Many guys run the 89mm LS/B20 crank and rods in vtec (gsr) blocks with great results!
Setup sounds like a good starting point. The extra strength and lubrication of the gsr block is never a bad thing.
I would look into possibly a ported head before you finish building it.The block will be built so all that is left is your head. If your head is already P+P'd, everything else will be easy as it will be more of a "bolt on".
Of course to truly exploit the engines potential, you will need bigger than stock cams and the valvetrain that goes with it.
Good luck with your build!