While testing the mild small-block 350, we compared the stock (200 hp) 350 hydraulic flat-tappet cam against the Nitrous HP NX256H with and without the nitrous. Replacing the mild factory cam with the NX256H resulted in a significant jump in power. The larger cam profile lost little, if any power down low, but showed significant power gains past 4300 rpm. The curve indicated that the engine would now pull strongly to 6000 rpm, where the power was falling off hard with the stock cam.
Before we performed the cam swap to the NX256H, we ran the Zex plate nitrous kit on the small-block equipped with the stock cam. Running the nitrous system on the 350 with both cams helped illustrate the power gains offered by the cam swap both normally aspirated, and with the nitrous. Running a 100-shot (46 nitrous jet and 43 fuel) through the Zex plate system resulted in a jump in peak power to 429 hp and 537 lb-ft of torque. The torque gains exceeded 100 lb-ft mostly because the nitrous was engaged low in the rpm range (3500 rpm). After replacing the stock cam with the NX256H, we once again installed the Zex plate nitrous kit, and ran the identical jetting and timing with the nitrous cam. The results were impressive. The nitrous system increased the power output of the 350 test motor from 399 hp to 500 hp, a gain of 101 hp. The torque gain was even more impressive, as the nitrous-equipped small-block thumped out 567 lb-ft of torque, a gain of 160 lb-ft.