Well the Robinson Racing pinions are all .48" long, which would mean there would be about 1/8" of overhang off the motor shaft length that I described. (Not overhang in relation to the spur/pinion mesh) That shouldn't be a big deal.

But to answer your question, simply measure one of your Novak pinions. If they're about half an inch long, you're in business. Any longer, and your pinion's gears may not perfectly align with your spur gear.