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Nitrous-Specific Cam Test - Bottle Built

Do nitrous-specific street cams really work? We hit the dyno to find out

By Richard Holdener, Photography by Richard Holdener
  • Nitrous Specific Cam Test Nitrous Plate
    After the baseline numbers were established with the stock cam, we installed the nitrous plate under the Barry Grant carburetor.
    Nitrous Specific Cam Test Nitrous Plate
    After the baseline numbers were established with the stock cam, we installed the nitrous p
  • Nitrous Specific Cam Test Open Plate
    The open plate acted as a carb spacer, which required changes in the jetting (by 4 jet sizes) to produce the desired air/fuel ratio. Once activated, the nitrous system upped the power output of the test motor from 343 hp to 429 hp.
    Nitrous Specific Cam Test Open Plate
    The open plate acted as a carb spacer, which required changes in the jetting (by 4 jet siz
  • Nitrous Specific Cam Test Cam
    After running the nitrous on the stock cam, we swapped in the NX256H cam from Comp.
  • Nitrous Specific Cam Test Prelubed Lifters
    We made sure to pre-lube the new hydraulic flat-tappet lifters (supplied with the cam) with Lucas 30W engine oil.
    Nitrous Specific Cam Test Prelubed Lifters
    We made sure to pre-lube the new hydraulic flat-tappet lifters (supplied with the cam) wit
  • Nitrous Specific Cam Test Valvetrain Assembly Spray
    One new product we used during the cam swap was this valvetrain assembly spray. This made lubricating the springs, pushrods, and valve tips much easier.
    Nitrous Specific Cam Test Valvetrain Assembly Spray
    One new product we used during the cam swap was this valvetrain assembly spray. This made
  • Nitrous Specific Cam Test Dyno
    Back on the dyno, the cam swap increased the power output of the normally aspirated 350 from 343 hp to 399 hp. This was further increased to 500 hp once we activated the nitrous. The gains offered by the nitrous were more significant with the dedicated nitrous cam.
    Nitrous Specific Cam Test Dyno
    Back on the dyno, the cam swap increased the power output of the normally aspirated 350 fr
Nitrous Specific Cam Test Chart Flow

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.

Nitrous Specific Cam Test Dyno Chart

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.

SOURCES
AFR COMP Cams
Barry Grant
Dahlonega
GA
706-864-8544
www.barrygrant.com
Zex
3418 Democrat Rd.
Memphis
TN  38118
By Richard Holdener
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