On the normally aspirated cam the Ford performed well, cranking out 532 lb-ft of torque at 4,200 rpm combined with a solid 502 hp at 5,600 rpm. Then we pulled back the timing 10 degrees and hit the nitrous. The big Ford literally jumped when we pressed the button, with peak torque rocketing up to a stunning 791 lb-ft at 4,000 rpm. Horsepower numbers also cranked to slightly more than the predicted 175hp gain to a killer peak horsepower of 670. What's interesting is the massive torque this engine cranked out at 4,400 rpm with a gain of 238 lb-ft of torque and 200 hp over the normally aspirated levels.
We swapped in the nitrous cam along with a new set of lifters, broke them in, and then re-baselined the new package to ensure it had the best timing and jetting combination. The first thing we noticed was that the midrange torque fell off, losing over 20 lb-ft of twist below 4,000 rpm compared to the normally aspirated numbers from the first cam combo. As we've explained, this was expected and due mainly to the nitrous cam's longer exhaust profile that opened the exhaust valve earlier. This tends to shift the torque curve higher up the rpm band, which sacrifices torque in the midrange.
On the nitrous cam, the big 466 lost torque with a peak of 529 lb-ft at 4,400 rpm, while the horsepower peak gained slightly with a best of 508 at 5,400. Under the category of compromises, this would certainly hurt normally aspirated acceleration. Now it was time to see what the big Ford would do on nitrous with the nitrous cam in place.
We loaded up a fresh Nitrous Pro-Flow bottle for our squeeze play, hit the button, and watched the power readout jump. Even with the early-opening exhaust lobe the torque spiked again under pressure, but when compared with the normally aspirated cam test, the overall power was down. As expected, we did see the nitrous power improve after the horsepower peak, but the gain wasn't worth the overall power loss.
Test 1: First normally aspirated baseline run with the Comp Cams XE 274H cam, Edelbrock Victor 460 single-plane intake, Holley 950-cfm HP Ultra carb, and 2-inch headers.
Test 2: Second baseline normally aspirated test with the Comp Cams nitrous camshaft. All other components remained the same.
Test 3: Nitrous Pro-Flow 175hp nitrous shot with the XE 274H camshaft. All other components remained the same as in Tests 1 and 2.
Test 4: Nitrous Pro-Flow 175hp nitrous shot with the Comp Cams nitrous camshaft.
The big single-plane intake also required an increase in jetting on the Holley to adequate
We also swapped to a set of Autolite race plugs with cut-back electrodes for all the dyno
This is what a happy nitrous plug looks like after an afternoon's worth of thrashing. The
To keep the nitrous pressure up, we used this simple electric space heater directed at the