what kind of internal engine modifications do i need to use nitrous systems??

 

It might help to know something about the engine your starting with and mileage etc....

 

We have a "N2O Tech" forum for questions like this. I'll move your post there. At the top of the N2O Tech forum topic listing, there are some threads "stickied", with basic info about nitrous systems.

What you need to do the the engine internals will depend on the size of the shot you are planning to spray. Up to 125HP on a stock LS1 should not be a problem.