Evaluating the whole field, we have four really good heads here, and, realistically, all the heads (except the stockers) are good choices. While the power differences are clear, the ultimate evaluation is in the car. While the Patriot head did perform well in most of our objective categories, keep in mind that it did so by the barest of margins.
We are attempting to show that simplistic peak-horsepower-head-banger conclusions are rarely the most accurate. If the sheer number of comparisons has made the decision-making process a bit more challenging, then we've done our job. If we take the stock iron heads value at $150 (which is roughly what they're worth) and divide it by 325.5 average horsepower, you get a ridiculously low $0.46/average horsepower, which is far less than any of the other heads-so the cheapest isn't always the best choice. We must also include a caveat about this dollar-per-average horsepower evaluation. Within the top three heads, the difference is barely more than a dime per horsepower. It's important to note that within these rankings that there is a very small differential between these heads. The Patriot came in a close Second based on a combination of good power and price, with the iron Vortec Third and the Dart aluminum 200 heads Fourth. The Speedway head won mainly on the strength of its very low price.
The equation is simple: Divide the price of the heads by the average horsepower number. One way to look at this test is by average horsepower per dollar. The point of this evaluation was to test all heads costing less than $1,000, which made it much more competitive even before the first test started. It doesn't really matter if a set of heads makes great power if its cost is out of reach. While torque and horsepower numbers are certainly alluring, there's yet a third very powerful equalizer: cost. So, what does this comparison tell us? It tells us that if your decision came down to overall power, you could choose any one of these top four and make a really good decision. After the numbers were crunched, you could throw a blanket over the top four heads (Patriot, Dart, Jegs, and Summit) with a mere 6 average horsepower difference between them and less than 3 hp between the top three. So we decided to average the horsepower of each test between 3,600 and 6,000 rpm. That means the average power between peak torque and peak horsepower tells a much more accurate story of the potential benefit to improving acceleration than do peak numbers. On the other hand, a typical street engine will spend 70 percent or more of its time in between peak-torque and peak-horsepower engine speeds. Few street cars hit peak horsepower rpm in the quarter-mile in high gear. While peak horsepower is interesting, it can be deceiving, as our test engine in a typical street car with a 3.55 rear gear and a three-speed automatic only experiences 6,000 rpm (or more) twice in a typical quarter-mile pass, hitting this rpm at the top of First and Second gear. This led us to one more evaluation that should shed far more light on the question of which head is the best.
On the plus side, the Vortec intake port flows 42 cfm better than the stock heads at 0.500-inch lift and 18 cfm better on the exhaust side. If you are considering Vortec heads, keep in mind that swapping them in will require these parts at additional cost. In addition, you must use guided rocker arms and center-bolt valve covers, and the intake manifold bolt pattern is unique, requiring a specific intake manifold. This added roughly another $160 to the price of the heads but allowed us to use 1.6:1 roller rockers to level the playing field against the other heads in the test. We anticipated this issue and used a set of Scoggin-Dickeymodified Vortec heads with the valve guides machined for additional clearance and fitted with better, Z28-style valvesprings. In stock form, the retainers hit the seals with valve lifts above this 0.450-inch figure. The main limitation with these heads in pure stock form is their inability to utilize valve lift above 0.450 inch. These heads were only used on a few models of Vortec truck engines, but their longevity is ensured because they flow so well. The production-based iron Vortec head represents one of the best budget investments for power for the small-block Chevy.