I am becoming interested once again in using spray. I have all stock internals in my motor. What is the safest way to go with nitrous? what kind of shot is safe? and will nitrous eventually kill my motor?

 

as long as you have the right safety equipment in place you will be fine.
FPSS, Window switch, A/F ratio tuned or monitored

up to 150hp can be run on stock internals

nitrous by itself won't kill your motor....any aftermarket modification reduces the long term life of your engine. As long as you have the car tuned for the power, and respect it, you can have years of trouble free fun.

 

I've been running the ZEX dry kit (125 shot) on my stock LT1 for some time now. It has a few saftey features built in. It is a very easy kit to install. I also run a custom tune with timing pulled, colder plugs gapped correctly, and bigger injectors for additional saftey.

I'm on my second 4L60E build and torque converter. I've also been through a set of universal joints and a blown head gasket since the N2O install. The nitrous didn't directly kill anything but it could have contributed by adding additional stress. A turbo, stroker, or blower could do the same. Just make sure the kit is set up properly with all the saftey stuff.