As Leon sort of eluded to, the HP and fuel mixture you get with the jets is dependent on your fuel pressure DURING THE RUN.

Static pressure may not reflect the actual flowing pressure. So giving a set of pill numbers to someone may or may not provide the desired results, depending on their fuel system capabilities.

If you run a separate fuel system with a tank up front, you are more likely to have a constant fuel pressure to the plates than if you simply tee off a line from the carb fuel supply.

In your case, you are only trying to deal with 100-150 HP so it may not be as critical as if you were adding 400HP of NOS, but even at 100HP you can lean a motor out if the fuel pressure drops too much.

Your jets - N34 - F32 at 6.5 lbs of fuel pressure and assuming 900psi bottle pressure, should provide 94hp with a N/F ratio of 5.2 I like to keep the N/F ratio between 5-7. (under 5 getting too rich, and over 7 getting too lean). At 7.5psi fuel pressure you have 102HP, but N/F ratio drops to 4.83.

If the fuel pressure during the run is 4.5 lbs, the same jets are now calculated at 79HP and the motor gets leaner with a N/F ratio of 6.2 (in the middle of the "safe" zone).

The same jets at 9 lbs of fuel pressure could give you about 112HP, but starts to get overly rich - a N/F ratio of 4.4.

With 4 jets (2 N & 2 F) and a known fuel system, I would probably run N38 F34 for a 100hp shot. With an unknown system, I would error on the safe side with a N38 F36

For the 150hp range, N46 F44 (for unknown fuel system) and N46 F42 if I knew I could count on 5.5 lbs of fuel.

Of course NOS bottle pressure also plays into the mixture formula. I base most of my calculations around 900PSI of bottle pressure, which should be close when the bottle temperature is about 80 degrees. Heating the bottle over 80 gives you a higher pressure, which will lean out you N/F mixture.

During the run, the bottle will cool from the start to finish, which will give you a richer mixture at the end of the run than at the starting line. (This is a lot more critical in a 400hp system than in a 100 to 150 HP system.) I generally have my bottle pressure about 950 before the purge. It will drop a little after the purge, giving me about 925psi at launch. After a 10 sec pass, the pressure is usually about 875psi, so I base my calculations on the average which would be 900.

I would like to see the timing closer to 34 degrees with the 100hp set up (as Leon suggested), and 32 if you use the 150HP setup.

There are a lot of variables in a NOS system, but with a little common sense, it can be a lot of fun and still safe for your motor.

Scott