The mission: Take a purse of about $2,750, a willing 388ci small-block, and make over 500 hp by adding some of the industry's best top-end bolt-on performance parts. To fulfill this tall but doable order requires an exceptional set of cylinder heads, a well-thought-outcamshaft design, and an intake manifold to supply the engine with sufficient airflow. As you already know, more air means more power.
Cylinder-head technology has advanced light-years from what was available only a generation ago. This is largely thanks to the combination of several key factors including lighter-weight components and flatter, more efficient valve angles formerly associated with high-end race stuff, producing the most efficient power measured under the curve.
Suffice to say, Air Flow Research (AFR) has been very busy staying ahead of the cylinder-head development curve, as evidenced by the recently released Eliminator series, an all-new cylinder head for street or competition that increases flow numbers significantly over any previous design. This new benchmark has been accomplished by completely redesigning the combustion chamber, ports, throat area, and valve job on a 23-degree head, creating a greatly improved cylinder head from top to bottom-with the flow numbers to prove it. At 0.500 inch lift this head flows an impressive 278 cfm on the intake side, which is a 17 cfm increase compared with the original design, which flowed less (though still respectable at 260 cfm). For even more power, you can expect a competition version by the time you read this.
Of course, when we first learned about the Eliminator heads, we had to see how well they would perform. Lucky for us, we're in pretty tight with AFR's cylinder-head guru, Tony Mamo, and we managed to bug him into letting us test a pair, but not just any pair; we actually got the very first pair. After describing our test mule, and at Mamo's recommendation, we opted to try out the larger 195 version over the 180s and set a date to meet him at the Westech Dyno facility, where we spent the entire day flogging his latest creation on our trusty small-block 388. A quick one-time pull wouldn't do anyone any justice, so we tested them in several configurations that included two Comp Cams camshafts (XE274H and XE284H), an Edelbrock Performer RPM Air Gap and an Edelbrock Victor Jr. intake, and two sets of Pro Magnum roller rockers (1.52 and 1.6 ratios). By the end of the day, we had made an unimaginable number of dyno runs and had our story. From mild to slightly wilder, we show two distinctly different combinations that both made incredible power; however, if you opt for the slightly more aggressive configuration shown here you can actually expect to save a cool $20. Check out the details, and be sure to e-mail us at chevyhi@primedia.com and let us know which combination is your favorite.
It's All About Flow, Baby
For our testing we used the new AFR 195 Street Eliminator cylinder heads on our 388 small-block. The final compression ratio using these heads is about 10.6:1 so 91-octane fuel is required for operation.
The new head is the result of intense research and development into the new Eliminator series. Mamo tells us that when he designs a new head like the 195 Eliminator, he begins at the combustion chamber, works his way up to the valve job, then tackles the ports. The combustion chamber's shape is critical to flow because it helps shape the umbrella of air coming off the intake valve, and helps direct the air into the exhaust port. The process of designing a performance cylinder head is largely rooted in old-fashioned trial-and-error, shaping almost everything by hand and using some epoxy. Only then is the finished product's final design digitally programmed so that it can be recreated to other cylinder heads on a CNC machine.