Max shot of NOS on a stock N/A 4.1?

I bought a 83 regal with a 4.1 for $300. I've changed the front and rear of the car so it will look like a 87 GN. I was just wanting the car to run a little faster. So I was wanting to know what is the max recommended shot of NOS the motor could take? I'll eventually convert it to turbo. Thanks Tim
If you are running that car at the shootout next year....get your times with a 25 shot and then use a 150 shot for the race;) I cannot take credit for this type of racing. Some other group has perfected it.:)