408 stroker with nitrous?

You can run 10.5++ Compression on Pump fuel with Nitrous. If I were you since you will not be using it very often, I would buy a secondary Small Fuel Cell maybe 1 Gallon or so and mount it up front in the engine bay and keep it filled with 110 Octane Race gas and use a Secondary Fuel pump mounted right under the fuel cell to pump that fuel only.

This way when you are Smacking the Juice you will stay away from detonation and you can keep your compression High enough so it will still be a Lively engine when not using the NOS. You will also want some type of ignition retard that gets activated when the Nitrous soloenoids are triggered. A general rule of thumb is to Retard the timing 2* for every 50 Shot of Juice. I would use a MSD Digital 6 ignition that requires no pills and adjusts with a dial. It has 2 step rev limiter, NOS Retard etc all in one package.

Heck if you back enough timing out of it you can do it all with 10.5:1 Compression on Pump fuel easily!