AFR’s New Black Hawk Third-Gen Hemi Heads Come in 3 Flavors

If you're a company that makes aftermarket cylinder heads for Detroit's most recent powerhouses, you've found yourself in a bit of a pickle in recent years, as mass flow rates for ordinary bread-and-butter OE cylinder heads have skyrocketed in a race for improved efficiency. Driven by the EPA (ironically, the federal agency hot-rodders love to hate), today's Detroit-built V-8s are wringing a lot more work from a gallon of gas than we ever predicted. A perfect example of this is the third-generation Hemi V-8, which even in its most diminutive form offers port flow exceeding that of the most powerful big-block V-8s of the 1960s.

This has been a boon to Mopar hot-rodders, who can simply clean and refurbish their existing OE Hemi cylinder heads and use the money saved for some other necessary part. Stock third-gen Hemi heads are literally too good to warrant a serious aftermarket assault on the product category—or are they? The performance bar for aftermarket Hemi heads would need to be significantly better to make the effort pay off, a scenario made more difficult because the Hemi has separate casting and machining operations for driver- and passenger-side cylinder heads.

Late last year, Air Flow Research (AFR) announced a new line of cylinder heads for the third-generation Hemi called the Black Hawk. The Black Hawk third-gen Hemi cylinder head lineup consists of three basic flavors—185cc-, 212cc-, and 224cc-sized intake ports—and compete in the third-gen Hemi aftermarket arena with just two other non-OE-based product lines: the street-oriented, smog-legal Edelbrock Performer RPM, and the race-oriented Bear cylinder head by Rhode Island-based Thitek LLC. For an engine family that's now 20 years mature, that isn't a lot to choose from, and it only underscores how good the factory third-gen Hemi offerings are.

Before we dive into the flow numbers of the three new AFR head offerings, some background: For the time being, AFR has so far only shipped the smallest of the three cylinder heads—the as-cast 185cc Black Hawk in high-compression, 69cc-chamber form (both assembled and bare). Air Flow Research plans to ship the 212cc and 224cc versions with CNC porting later in 2023. Black Hawk heads are made from A356 aluminum and feature a .750-inch-thick deck to handle boost. Water jackets retain a minimum of .200-inch port-to-water-jacket thickness, and valvetrain geometry is designed for use with hydraulic roller camshafts up to .650-inch lift.

For now, the Black Hawk 185cc port volume version is only available with a 69cc combustion chamber, but may in the future be available with 73cc chambers. (Summit Racing is offering them here for $1,686 assembled, each; and $1,395 bare, each.) These as-cast heads flow 334 cfm on the intake side at .650 inches of lift and have 75cc exhaust runners, 2.050-inch intake valves, 1.590-inch exhaust valves, and sport 1.290-inch diameter PAC Racing dual valvesprings rated to .600 inches of valve lift. Assembled heads come with stainless-steel valvespring retainers, 10-degree valve locks, and Viton valve seals. The preliminary flow numbers provided by Air Flow Research are compared below with flow numbers from a stock 392 Hemi "big gas engine" (BGE) cylinder head with stock valves, a cylinder head that shares its port shape and flow rate with the Hellcat Redeye Hemi head.

In comparing these figures, it's important to note that Dodge Direct Connection sells a complete Hellcat Redeye cylinder head kit (with the Hellcat's larger 2.14-/1.65-inch diameter valves) for just $2,595, which comes in at hundreds less than the AFR offerings and also includes rocker arm assemblies, gaskets, and fasteners. As we said up front, the stock offerings are good, and at this performance level something would have to give price-wise to put AFR in a competitive position around its 185cc offering. Its smaller valve sizes, however, may make the AFR setup the hot ticket for smaller-bore (3.92-inch) 5.7-liter Hemis that can't accept the Hellcat Redeye's larger valves.

Moving on to the 212cc intake runner Black Hawk, we have a true step up in flow rates from all the third-generation OE Hemi cylinder heads, besting the Hellcat Redeye heads by over 30 cfm at .650-inch lift. They feature CNC-machined 212cc intake and 75cc exhaust runners, a choice of 69cc or 73cc CNC-profiled combustion chambers, larger 2.125-inch intake and 1.650-inch exhaust valves, and 1.290-inch diameter PAC Racing dual valvesprings rated to .600-inch valve lift. Assembled heads come with titanium valvespring retainers, 10-degree valve locks, and Viton valve seals.

The thing to keep in mind with any cylinder head boasting "CNC porting" is that a CNC port is only as good as the port it's copied from. In the case of the Black Hawk 212, the increase in high-lift flow has not come at the expense of mid-lift or low-lift flow relative to the as-cast 185cc version, and even has a slightly smaller-than-Hellcat-size intake valve. This tells us that Air Flow Research has done a lot of proper R&D work developing the port shapes beyond what the OE has done, and that's a tough ask with today's factory engines. With a flow rate of 375 cfm at .700-inch lift, the Black Hawk 212 head is comparable to some of the big-block Chevy race heads on the market, and theoretically ought to be capable of feeding around 770 hp in naturally aspirated form.

At the top of Air Flow Research's third-gen Hemi heap is the company's take-no-prisoners 224 Black Hawk, which flows 393 cfm on the intake side at .650-inch of lift. They feature CNC-machined 224cc intake and 75cc exhaust runners, 2.165-inch intake and 1.650-inch exhaust valves, 1.270-inch diameter PAC Racing dual valvesprings rated to .600-inch of valve lift, and a choice of 69cc or 73cc combustion chambers. Like the 212 head, assembled Black Hawk 224 heads come with titanium valvespring retainers, 10-degree valve locks, and Viton valve seals.

With AFR's advertised flow rates on the Black Hawk CNC 224 head, it's safe to presume it's the highest-flowing third-gen Hemi head out there—once it becomes available to the public. The only other head that comes close is the Thitek Bear head, which, thanks to some very good industrial secrecy, is whispered to support between 373 and 379 cfm at .650-inch lift. At this level of performance, an engine builder will encounter a flow restriction from commonly available intake manifolds, so the Black Hawk 224 is best used in conjunction with some form of boost. Naturally-aspirated applications will need to look at a custom sheetmetal intake or a single-plane intake such as the Drag Pack intake by Kent Ritter or the Prefix ARR-CAS-1010 (both shown above).

One final noteworthy thing potential buyers will want to be on the lookout for is that both of the Black Hawk CNC-ported options (the 212cc and 224cc versions) come drilled for both a naturally aspirated bolt pattern (holes are midway along the port shape in the style of Eagle, Apache, and BGE heads) and the Hellcat supercharger bolt pattern (holes along the outer perimeter). This is shown above on the right side of the image. The 185cc Black Hawk cylinder head (left) is only available with the naturally aspirated bolt pattern, but AFR says drilling the head for the OE-style IHI supercharger mounting pattern shouldn't pose a problem.

David Freiburger and Steve Dulcich are no strangers to junkyard engines and bizarre modifications on Roadkill Garage. On Engine Masters, they take that to the next level, adding crazy upgrades to stock or scrapped Hemi and Mopar engines. Check out this compilation of junk engine rebuilds. Sign up for a free trial to MotorTrend+ and start watching every episode of Engine Masters! Video created by Little Dot Studios.