We often try our best to get the most performance possible from our engines. In the search for more power, we often remove exhaust manifolds and swap them out for a set of headers. Available in various configurations, such as "shorty" headers, long tube street use, and long tube tuned racing headers gives us many options. Long tube headers are usually favored, even if the vehicle they are going in is a dedicated street machine and not an all-out racer, but some header designs can hang low, causing them to be damaged all too easily. There are headers available that provide us with more ground clearance, but they are usually far from what can be considered budget pieces. Some enthusiasts regret the move to tube headers due to fitment problems, leaks, and other assorted issues.
As of late, there appears to be a trend toward short-tube headers for street vehicles. These shorter tube headers have increased ground clearance, but we have to wonder how much they compromise performance. If you own a Ram or Dakota that is equipped with a 5.2 or 5.9 Magnum, "shorty" headers are almost the only option available to bolt to the stock exhaust. On the other end of the scale, there are street vehicles that are fitted with larger diameter long-tube race headers due to the owner's desire to get maximum performance at any cost. We recently tested a few of these options to see if there is any clear advantage to using a certain design over another in a street performance application. Our budget street 360 was called upon to test the various designs, as stock manifolds and small headers would be a big restriction on an all-out race build. This would also be good for testing a street versus race design in a mild application. This engine is a low compression LA engine with factory iron heads, a Mopar Performance dual plane intake, Holley 670 carburetor and a mild hydraulic camshaft from Competition Cams.
We started our test session with a set of 5.9 Magnum exhaust manifolds adapted to the dyno's exhaust. With a set of adaptor pipes we had made up for us at our local exhaust bender, we were able to route the exhaust gasses out through the dyno mufflers. Using these adaptor pipes and Magnum manifolds allowed us to swap directly to a set of shorty truck headers and keep the tests as equal as possible. We mounted the manifolds and adaptor pipes to our 360, and made our initial test pull. Our test pulls were the same for all testing, with a starting rpm of 2,000, and ending at 5,800. Our peak numbers showed 347.9 lb-ft of torque at 3,200 rpm and 292.8 horsepower at 5,200 rpm.
Next, we bolted on our Pace Setter shorty headers. With 11⁄2-inch primary tubing and such short tubing lengths, we had to wonder if there would be much of an improvement over the manifolds. We were pleasantly surprised with the output, having a nice increase in torque right from the start, and carrying the extra power throughout most of the pull. Our peak numbers were now 355.7 lb-ft at 3,000 rpm, and 316.3 horsepower at 5,200 rpm.
Moving on to a set of Hooker 15⁄8-inch street headers that are typically used by most budget minded builds, we lost most of the torque we had gained very early in the pull, but by 2,500 rpm, we caught it and then saw a nice increase in power shortly thereafter. Our peak numbers were looking better, with our peak torque at only 2,800 rpm being 364.9 lb-ft. Our horsepower was up also, now coming in with a peak of 325.1 horsepower at 5,400 rpm.
The last test was to bolt on a set of 13⁄4-inch Hooker Super Comp headers. Aimed more at the racing end of the scale, and being the next larger size, we were not too surprised to lose a little more torque down low. What may come as a surprise to some is that the power did not catch up with the street headers until the very end of the pull. The loss of torque was great enough to make us take notice. Our peak torque numbers were now 357.1 lb-ft at 3,000 rpm, and the horsepower was now 323.9 at 5,400 rpm.
What can be learned from this is that, like carburetors, the old adage "bigger is better" is not always true. We also learned that even with what looks to be a compromised design due to the very short and small diameter tubing, the shorty headers offer a distinct advantage over what could be considered a fairly free-flowing factory exhaust manifold. Moving up to a street style long tube header may very well net you some gains in power, but you have to decide if the gains are worth the frustration they can often bring.
|Pace Setter shorty headers