14 psi on stock internals is not the greatest idea for one, BUT, LS motors do respond well to nitrous... If you can keep a safe air fuel ratio across the board you should be able to spray a decent shot... I have seen stock LS bottom ends hold a 120 shot, but I wouldnt reccomend anything more than about 80... To do this safely you must run a wet shot and upgrade your fuel pump... theres nothing worse than having good a/f ratios on a dyno then going out to a different climate/environment and having everything go haywire... Also, slightly retard the timing via the distributor or invest in a jacobs nitrous controller.... from there you can slowly work up and with constant care, maintenance, and tuning, i don't see why a 100 shot would be a problem.... Just make sure to check everything over and make sure everything tuning wise is on the money before you go to crazy...

Also, I do NOT reccomend higher compression with nitrous as this will further increase horsepower and test the limits of the internals of your motor... This also goes for high mileage motors that have developed a carbon build up on the pistons that can cause compression to be raised...
I am by no means a nitrous expert, and with that being said, I say find someone who works with it on a regular basis and has that experience to tell you if anything I said was inaccurate....

Hope that helps some....