AFR’s Enforcer Cylinder Heads Raise The Bar For Budget Performance

Whether you are building a whole new engine, or just trying to add some power to your current project car, cylinder heads are a crucial component. As the gatekeepers to your cylinders, the head plays a part in everything from the shape of the power curve to the actual power numbers.

Playing such an essential role in your engine, new cylinder heads usually come at a significant cost, for a variety of reasons. Cylinder heads are an inherently complex part which requires significant precision in the casting and manufacturing processes, not to mention the cost of creating the molds in the first place.

When you add in the time for R&D and CNC-machining to shape the ports and combustion chambers that Air Flow Research is known for, the selling price of the heads is understandable. However, looking for an affordable middle ground, AFR came up with its new line of cylinder heads — The Enforcer. “[The Enforcer] is aimed at anyone on a limited budget, looking for aftermarket heads with high-quality components from a brand they can trust,” says Tim Torrecarion, marketing and sales director for AFR.

New Name, New Value

While the AFR name is synonymous with amazing CNC-ported runners and combustion chambers, the company earned its reputation through knowledge of airflow. By applying that knowledge into all-new castings, they can incorporate things like desired runner-volume and shape, combustion chamber shape and volume, and other design features right into the molds.

Previously the cylinder head castings started as a basic casting for the CNC machines to work their magic on. Now, the magic is contained within the casting itself. This allows AFR to offer a cylinder head with improved port designs and enlarged port volumes but without any of the expensive CNC porting or finishing work (other than the critical surfaces like the deck and valvetrain mounts).

“The port designs and castings are completely different than our full-CNC heads,” Torrecarion explains. The “as-cast” ports and chambers save a significant amount of production expense, while still performing better than an OEM or other budget cylinder head. Additionally, by limiting the number of available options on this line of cylinder heads, AFR can further streamline the manufacturing process, keeping the prices in the realm of affordability.

While the Enforcer line might be a budget-oriented cylinder head, you wouldn't know by looking at it. All of AFR's traditional quality-control checks are still performed and standards are maintained in the Enforcer lineup.

Initially offered in four fitments — small-block Chevy, cathedral-port LS1, big-block Chevy, and small-block Ford — the heads do share some features across the line. All of the Enforcer cylinder heads are manufactured using permanent-mold castings and feature the as-cast surface finish on the intake and exhaust runner walls and combustion chambers.

Each offering will be available in one of two configurations. Bare (or “No Parts” in AFR vernacular) or fully assembled. The assembled heads feature the same components used in AFR’s more expensive cylinder heads, so there are no worries about any corners being cut there.

ARP rocker studs, PAC Racing valvesprings, Viton valve seals, hardened spring cups, ductile-iron valve seats, machined locks, AFR guide plates, and AFR’s stainless-steel valves are all included on the assembled heads. While the exact specs on those parts will vary by application, their quality is assured.

Big-Block Chevy Enforcer

The big-block-Chevy variant of the Enforcer heads is a 325cc rectangle-port design, which holds its own, given the price point. The 325cc intake runner flows 355cfm at .700-inch lift, and the Enforcer exhaust port actually outflows the 2101 port at .700-inch lift by 2cfm, proving the as-cast runners can perform with the big boys.

The 122cc combustion chamber houses a stainless 2.250-inch intake and a 1.880-inch exhaust valve, both in 11/32-inch stem diameter, riding in bronze valve guides. The 1.55-inch OD dual valvespring is designed for hydraulic-roller street applications. It features 175 pounds of seat pressure and will handle .725-inch of valve lift at 6,700 rpm, which should be more than enough for the intended market.

The big-block Chevy Enforcer package is meant for big-flow, even with as-cast features, such as the 325cc intake ports (left), the 122cc combustion chamber with openings for 2.250-inch and 1.880-inch valves (center), and 140cc exhaust runner.

The spring is retained by a steel 10-degree retainer and steel valve locks, coupled with adjustable pushrod guide plates. Bare heads will carry the part number 3002, while fully assembled heads will be P/N: 3001.

AFR BBC Enforcer Cylinder Head Flowsheet

LIFT 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900
Intake 156 228 286 326 342 355 364 367
Exhaust 138 189 226 254 271 282 290 298

Cathedral Port LS1 Enforcer

The Enforcer LS heads are listed as LS1 heads, simply because the cathedral-port head requires a 3.900-inch minimum bore size to fit the intake and exhaust valves without undue shrouding or potential outright physical contact.

The 210cc intake runner flows 262cfm at .600 inch of lift, while the 82cc exhaust runner flows 207cfm at the same .600 inch of lift – which is better than 243/799 flow numbers we’ve seen, on both sides of the head.

The 64cc combustion chamber volume allows for decent compression numbers. It houses a 2.020-inch stainless-steel intake valve and a 1.600-inch stainless exhaust valve, both in the familiar 8mm small-block stem diameter and riding in bronze valve guides.

Here you can see the LS Enforcer cylinder head's 210cc cathedral intake ports, 64cc combustion chamber with 2.02/1.60 valves, and 82cc exhaust port. According to the flowchart below, these heads flow more than the exceedingly popular OEM 243/799 cylinder heads. They are listed as "LS1" heads, as they require a minimum 3.900-inch bore, so 4.8L/5.3L-bore engines need not apply.

The assembled version of the head features a premium-grade, chrome-silicon 1.290-inch-diameter dual valvespring with 140 pounds on the seat and is good for .600 inch of maximum lift at 6,500 rpm. Those specs will cover what’s found on a typical street LS engine.

Holding those springs in place is a set of steel 7-degree retainers and AFR’s standard 7-degree 8mm valve locks. The bare “No Parts” version of the LS Enforcer head will carry the part number 1502, while the fully assembled version will be P/N: 1501.

AFR LS1 Enforcer Cylinder Head Flowsheet

LIFT 0.200 0.300 0.400 0.500 0.550 0.600
Intake 148 209 253 268 262 262
Exhaust 105 150 180 199 204 207

Enforcer vs. OEM LS

Since we know everyone in the LS world is going to ask how and why these heads are better than the best OEM cathedral-port cylinder heads, we decided to pose that exact question to Torrecarion directly. “Performance-wise, I would say the Enforcer and 243/799 heads are comparable,” Torrecarion explains. “But, the main advantages of the Enforcer heads are that they are brand new versus used, and that they come with high-quality valvetrain components — PAC Racing valvesprings, Viton valve seals, hardened spring cups, machine locks, ductile-iron seats, and AFR stainless-steel valves. Those are the same components you get with our full-CNC cylinder heads.”

Windsor Small-Block Ford Enforcer

AFR’s Enforcer small-block Ford cylinder heads make a great budget-friendly alternative to the class-leading Renegade lineup of cylinder heads. With a 185cc intake runner size, the heads fall into the larger side of the 302-based street engine offerings while still being large enough to provide an upgrade in a 351 Windsor engine.

The 185cc intake runner flows 262cfm at .700 inch of lift, and the 64cc exhaust runner flows 168cfm at the same lift. Like the LS version, the SBF Enforcer features 8mm-stem, 2.020-inch-diameter stainless intake valves and 1.600-inch stainless exhaust valves in bronze valve guides.

The small-block Ford Windsor's port sizes will work with bolt 8.2-deck 302-based engines and 9.5-deck 351W-based combinations.

The SBF Enforcer uses the same premium-grade, chrome-silicon, 1.290-inch-diameter dual valvespring as the LS head. With 140 pounds on the seat, it is good for .600 inch of maximum lift and 6,500 rpm, which is about the most a typical street-based hydraulic-roller or solid-flat-tappet Windsor engine will see.

Since it uses the same spring and valves as the LS head, it only makes sense that the SBF Enforcer uses the same 7-degree steel retainers and valve locks, too. However, unlike the LS head, the SBF version features an adjustable pushrod guide plate. The bare head will be part number 1352, and the assembled head will be P/N: 1351

AFR SBF Enforcer Cylinder Head Flowsheet

LIFT 0.200 0.300 0.400 0.500 0.550 0.600 0.650 0.700 0.750
Intake 119 177 225 255 257 257 260 262 264
Exhaust 105 143 163 166 168 170 166 168 168

Small-Block Chevy Enforcer

The AFR Enforcer small-block Chevrolet head retains the standard 23-degree valve arrangement and is the only variant in the Enforcer lineup with two different configurations available. Like AFR’s other SBC cylinder heads, the Enforcer is available in both straight and angled-plug configurations.

The 195cc intake runner flows 251cfm at .600 inch of lift, while the 76cc exhaust runner moves 197cfm at the same lift. Like both of the other small-block options, the SBC variant features 2.020-inch stainless intake valves and 1.600-inch stainless exhaust valves with an 8mm stem, with bronze valve guides.

AFR worked hard to make the Enforcer 195cc small-block Chevy cylinder heads stand out in a very crowded marketplace.

The SBC heads use the same 1.29-inch chrome-silicon valvesprings along with 7-degree locks and retainers as well. This parts-commonality not only means replacement parts are readily available should they ever be needed, but it also keeps the costs down through sheer volume.

Good for .600 inch of valve lift and 6,500rpm out of the box makes these a significant upgrade over any junkyard head available, and covers most hydraulic roller or mechanical flat-tappet street applications. The bare, straight-plug version will be part number 1002, while the fully assembled straight-plug head will be P/N: 1001. The angled-plug heads will be P/N: 1007 for a bare head and P/N: 1006 for the fully assembled version.

AFR SBC Enforcer Cylinder Head Flowsheet

LIFT 0.200 0.300 0.400 0.500 0.550 0.600
Intake 133 188 226 250 251 251
Exhaust 104 138 158 186 191 197

Looking at all of the specs and flow data for the new Enforcer line of cylinder heads from Air Flow Research, it appears the team from southern California found a way to  provide significant performance increases while still staying well within a budget application.

It is fair to say, if these heads perform as well in the real world as they do on paper — which is a safe bet based on AFR’s reputation — they will be punching way above their price point, and give the street enthusiast on a budget a new, high-performance cylinder head option. Whether it’s a small-block Chevy, LS, small-block Ford, or big-block Chevy, the Enforcer lineup proves you don’t need to spend big money for big power.

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About the author

Greg Acosta

Greg has spent fifteen years and counting in automotive publishing, with most of his work having a very technical focus. Always interested in how things work, he enjoys sharing his passion for automotive technology with the reader.
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