On a recent trip to Vrbancic Brothers Racing to witness a dyno pull, we had the chance to chat with Bob and George about the various project engines in their shop. One of their customers brought in an all-stock engine. He wanted to really punch out the ponies with this engine, but didn't want to get rid of the OEM heads. Not for any numbers-matching, auction house reasons, he just wanted a stock appearing engine.
Although an attempt was made to dissuade him from this path for the simple sake of economics and flow numbers, he still insisted that the OEM heads be rebuilt. Admittedly, most of us can probably identify with this situation. Sometimes it's just downright cool to see an old set of double hump heads on top of an engine.
Looking old school cool does come at a price, though. Unless you own a machine shop, there's a good chance that the costs will easily cross the $1,000 mark with upgrades such as cleaning an old set of double hump heads, adding hardened seats, grinding the seats, porting and polishing, fitting new guides, and installing screw-in rocker arms, studs, seals, springs, valves, etc.
It used to be that this was the only way to have higher flowing heads. Most early racers had a secret scientist locked away in a tower where he worked night and day getting those asthmatic heads to breathe. A majority of those old racers were pretty tight lipped about the performance of their heads. Well, the secret is out of the bag-and has been for several years now. The performance of yesteryear's racers is now standard operating procedure for various aftermarket cylinder head companies.
We called all the cylinder head manufacturers we could think of and asked them what their most popular off-the-shelf performance cylinder head is. We also told them that we wanted to present our readers with performance heads available on a realistic budget (given that "realistic" budgets tend to range quite a bit). Judging by the responses we received, it seems the majority of today's bang-for-the-buck performance cylinder heads are the out-of-the-box, pre-assembled type. In no particular order, here's that list we compiled. Stay tuned for next month's big-block cylinder head list.
GM Performance Parts
Vortec 170cc Cast-iron SBC Cylinder head
One of America's favorite high-performance, cast-iron, small-block cylinder heads offers big power at an incredible value. The modified combustion chambers and high-velocity port technology offer impressive power gains at an affordable price. The Vortec head significantly outflows their non-Vortec service replacement head and offers a 20-40 hp increase over earlier cast-iron heads. They will fit 1955-and-later small-blocks, except for the LT1/LT4 and LS family of engines. (These heads do require Vortec-specific intake manifolds).
Air Flow Research
AFR 180cc and 195cc SBC Eliminator Street Cylinder Head
AFR's new "Eliminator" SBC line raises the bar for 23 cylinder-head technology. Completely redesigned castings feature improved oil drain back, stronger rocker stud bosses, and revised cooling passages. A clean sheet of paper approach to port and combustion chamber designs has boosted efficiency levels dramatically with smaller cross-sectional areas flowing 5-10 percent more across the entire curve for increased airspeed. AFR is the first company to incorporate "Gen III" technology into their 23 product line by fitting them with 8mm valves, and lightweight springs and retainers (a 50-gram weight reduction per valve/spring/retainer assembly), which reduces valve float and improves high-rpm power and reliability.
The AFR Emissions Legal (versions from 1969 to 1994 with heat riser, CARB EO #D-250-2), 180cc intake port small-block Chevy cylinder heads are available in your choice of straight, or L98 angle plug versions. The 180cc heads feature a 74cc or 68cc combustion chamber with a 64cc exhaust port and a 3/4-inch thick head deck (ideal for nitrous or blower applications.) The 68cc chambers are designed for flat top or dished pistons; domed pistons will require additional machining. Standard valves are 2.020 intake and 1.600 exhaust with AFR's hardened ductile iron interlocking valve seats. The exceptional flow characteristics, ideal operating range of idle to 5500 rpm (higher rpm ranges possible depending on combination of parts), 23 valve angle, and standard valve spacing make this the perfect street head for 327 cid to 350 cid engines from 1955 to 1986. They're also available for 1987-to-present engines with center bolt valve covers and two center intake bolts at 72 angle. No special parts are required for these heads.
Sportsman II 200cc Iron SBC Cylinder Head
Continuously improved since its 1987 introduction, the Sportsman II is still the industry's most popular cast-iron high-performance head. Featuring RightCast 200cc intake runners, Fast-Burn chambers, and your choice of angled or straight plugs, they're good for 30-70hp increases right out of the box. They're the aftermarket's only 50-state emissions-legal, cast-iron, high-performance cylinder head (E.O. #D-343-1). World Products heads are precision CNC-machined, and indexed off the chambers to assure perfect alignment with the cylinder. They flow 238 x 134 @.600 as-cast.
Cost per pair: $645.98 (bare); $968.98 - $1101.98 (assembled).
S/R Torquer 170cc Iron SBC Cylinder Head
An improved replacement for the factory Chevrolet 327-350-400 cylinder heads, World's S/R Torquer series features 170cc intake runners, and can provide up to a 30hp increase over most OEM castings. Note, however, that these heads are accepted by many racing associations as "stock," and are 50-state emissions legal. S/R Torquer heads accept early and late model accessories. The exhaust valve seats are hardened to provide compatibility with unleaded gas. The S/R Torquer heads are available in 67cc and 76cc versions for engines up to 1986, and 76cc for 1987-and-later applications. They are designed to use 2.020-inch intake and 1.600-inch exhaust valves. They flow 206 x 116 @.600 as-cast, and work well in engines from 302 to 400 cid.
Cost per pair: $598.48 (bare); $883.48 (assembled).
Motown 220cc Cast-iron SBC Cylinder Head
Designed to provide an even greater intake charge than the Sportsman II, World's Motown 220 features the latest high-tech 64cc chambers and RightCast 220cc runners to provide a combination of excellent flow and high velocity. With high-flow ports (flow: 269 x 169 @.600 as-cast) and standard intake valves, Motown 220 heads are the ideal complement to large displacement small-blocks (383 cid and larger).
Cost per pair: $655.48 (bare); $1101.98 - $1291.98 (assembled; with your choice of straight or angle plug configurations).
Freedom 188cc Aluminum SBC Cylinder Head
Patriot Performance's new Freedom Series heads provide exceptional quality and great performance. The intake and exhaust runners on these heads were modeled after its CNC ported heads and flow 260 @ .600-inch using a 188cc intake runner. The combustion chamber volume on these heads will be 64cc, and castings will be available in straight or angle plug. The 188cc Freedom heads are designed for street/strip applications and are equipped with the following: 2.02/1.57 21-4N stainless steel valves, steel retainers, .575-inch lift springs, custom honed bronze guides, machined spring bases, viton rubber seals, 3/8-inch studs, and guide plates. A 220cc runner version and a BBC version will be coming soon. These heads will fit all '55-and-up GM 23 small-block engines (except LT1).
Cost per pair: $795.00 (assembled).
IK 180cc & 200cc Aluminum SBC Cylinder Head
These new small-block heads offer the only two things that matter: performance and price. New features for the IK 180/200 include a revolutionary ultra-casting, versatile 180cc or 200cc intake ports that are specifically designed for optimum versatility, and 64cc or 70cc combustion chambers. 2.020/1.600 intake and exhaust valves allow the use of several types of fuels. Standard features include: A-356 virgin aluminum alloy, phosphorous bronze valve guides, valve seats for use with unleaded fuel, ends milled and drilled for accessories, and a straight spark-plug angle. CNC ported combustion chambers are available as large as 74 cc. These are the most affordable high quality aluminum cylinder heads on the market.
Cost: $1,070 (for assembled heads).
Race Rite 180cc & 200cc Aluminum SBC Cylinder Head
These Race-Rite heads from Brodix for small-block Chevys are available with 180cc or 200cc intake ports. They feature 67cc combustion chambers, 2.020/1.600 intake and exhaust valves on the 180cc, and 2.055/1.600 intake and exhaust on the 200cc models. These aluminum CNC-machined, fully assembled heads can be used in street and strip applications. Brodix installs solid, phosphorous bronze guides, and ductile iron valve seats reducing valve leakage and oil consumption.
Cost: The assembled 200cc retails for about $1,329.
EQ Cast 180cc & 200cc Iron SBC Cylinder Head
Enginequest stock replacement and performance cylinder heads are designed to provide maximum power with minimum effort. They're engineered and manufactured in a state-of-the-art facility and are available from over 300 different retailers. All EQ 23 cylinder heads feature specially designed runners and combustion chambers (available in 50cc, 64cc, and 72cc volumes) to maximize velocity, volume, and atomization. Their improved valve guide material allows for tighter tolerances and extended durability. The heads are available in cast-iron, and straight or angled spark-plug configurations. EQ Lightning Heads accept 1.55-inch diameter springs and standard style rockers. All performance cylinder heads have the following: as-cast combustion chambers and ports, Dura Bond exhaust seats, a three-angle valve job, thick deck faces for angle milling, phosphor bronze intake, and exhaust guides machined for guide plate use.
Cost: $860.50 K1 (hydraulic flat tappet up to .550 lift-1.460-inch single w/damper 110lbs @ 1.800-inch); $899.50 K2 (solid flat tappet or hydraulic roller up .600 lift-1.460-inch dual w/damper 135lbs @ 1.800-inch).
Powerhouse Engine Components, Inc.
Powerhouse 190cc Aluminum SBC Cylinder Head
You've seen the ads in Super Chevy that read: "Home of the 383 Stroker Kit." Did you know Powerhouse also makes and sells cylinder heads? Powerhouse aluminum cylinder heads feature a 64cc chamber/190cc intake runner, and a spring setup for .550-inch flat tappet hydraulic cams (upgrades available). Heads feature 2.05-inch x 1.60-inch stainless steel, swirl polished valves, .550-inch lift (1.460-inch OD) dual valve springs, chrome-moly retainers, 10 hardened valve locks, high-temp valve seals, and bronze guides. The straight or angled plugs both include 3/8-inch screw-in studs and guideplates (and require +.100-inch long hardened pushrods).
Cost: $799 (assembled).
Holley Performance Products
Avenger 184cc Aluminum SBC Cylinder Head
Holley Performance Products is proud to introduce the latest addition to its line of aluminum cylinder heads for 305, 327, and 350ci small-blocks built up to 1986. The Avenger heads are cast 356 aluminum, heat treated to T-6 for strength and then CNC machined to exact tolerances. A .500-inch deck thickness was designed into the casting to give maximum strength and to improve gasket retention. All rocker stud and exhaust manifold bolt holes are heli-coiled for added strength and durability. The Avenger heads offer a 20-degree valve angle design to help optimize the intake and exhaust runner flow, but still retain the stock port locations for intake manifolds and exhaust headers. The heads come fully assembled with one-piece stainless steel swirl polished under-cut 2.02-inch intake valves and 1.60 exhaust valves; hardened steel guide plates; ARP rocker studs; and Lunati valve springs, locks, and retainers capable of handling the high-lift camshafts. The port-matched 184cc intake and 68cc exhaust runners are port-matched to ensure maximum flow, horsepower, and torque. In most cases the Avenger heads can be interchanged with factory heads. The 68cc combustion chambers are performance-designed to keep compression ratios down for use with pump gas, and the spark plug location has been optimized for better combustion.
Cost: $1,400 (MSRP).
Aerohead Racing Components
Aerohead Cast 165cc Iron SBC Cylinder Head
Aeroheads are reconditioned and come assembled with a "like new" appearance and quality, all new Aeromaxx parts installed, and a milled deck surface. These heads have outstanding features that include premium one-piece, stainless steel, high-flow valves; heat treated and machined steel retainers and valve locks, seals, bronze wall valve guides; a 3-angle valve job; and heavy duty valve springs. All heads listed accept their respective stock equipment (i.e. intake manifolds, exhaust headers and manifolds, valvetrain, valve covers, and accessory bolt holes). The heads also offer a modern, fast burn combustion chamber design.
RHS (Racing Head Service)
Pro Torker 1 170cc Iron Vortec SBC Cylinder Heads
Once again proving its commitment to "Power by Design," the new RHS Pro Torker Vortec Iron Performance cylinder heads deliver superior flow characteristics over all other previously available iron small-block Chevrolet heads. In comparison to the popular GM 906 casting, the RHS Pro Torker Vortec cylinder heads deliver 27 more cfm at 0.500-inch lift. Constructed from high quality cast-iron, these heads are perfect for racing classes where iron heads (with standard 2.02-inch intake and 1.600-inch exhaust valve sizing) are required. Featuring dual pattern (four and six bolt) intake compatibility, these heads work with virtually any intake manifold (including early style) rather than being restricted to Vortec-style components, which has been a limiting factor in the past.
Equipped with hardened exhaust seats, multi-angle performance intake valve seats, and "Fast Burn" 64cc combustion chambers, the new RHS Pro Torker Vortec heads are perfect for both race and street performance applications. Featuring spring seats specially machined for 1.550-inch valve springs, and premium bronze valve guides designed to avoid potential retainer to guide clearance issues when used with high lift camshafts, RHS delivers the ultimate in high quality, high-flow cylinder head technology with its new Vortec SBC Iron Performance Cylinder Heads. Features include: a 170cc intake runner, multi-angled intake valve seats, radiused exhaust valve seats, a 1.550-inch valve spring seat, improved retainer-to-guide clearance, hardened valve seats, extra-thick deck faces, and a dual pattern (early and late model) intake manifold compatibility.
Cost: $450 (assembled; flat tappet).
RHS (Racing Head Service)
Pro Action 200cc Iron/Aluminum SBC Cylinder Heads
The new Pro Action cylinder heads use advanced airflow and cooling technology to deliver the most "out of the box" power and torque available, claims RHS. A manufacturing process labeled Clean Cast Technology ensures that its products meet strict tolerances and achieve superior final workmanship in order to eliminate the need for extensive after-purchase porting. As an added benefit, the refined RHS water jacket design flows much better than the competition, delivering improved heat dissipation and yielding more consistent and reliable horsepower.
Pro Action 23-Degree SBC Cylinder Heads feature specially designed runners and combustion chambers (available in 50cc, 64cc, and 72cc volumes) to maximize volume, atomization, and velocity. An improved valve guide material yields tighter tolerances and extended durability. Available in aluminum or iron, and straight or angle spark plug configurations, Pro Action SBC cylinder heads accept 1.550-inch diameter springs, and standard style rockers and valvetrain. Options include as-cast, CNC'd chambers, or matched assemblies utilizing Comp Cams components. Standard features include multi-angle intake, and radiused exhaust valve seats for up to five percent more flow and improved guide and seat material. Select from 180cc, 200cc, 220cc, and 235cc intake runners, and 50cc, 64cc, and 72cc combustion chambers.
Cost: $626 (assembled).
Iron Eagle Platinum 180cc Cast-iron cylinder SBC Cylinder head
Dart has developed more efficient port designs with improved velocity and flow capabilities, and the results are the Iron Eagle Platinum cylinder heads. The combustion chamber of these heads has been redesigned, and the casting walls made cleaner, for greater breathing characteristics and more controllable combustion. Also featured are hardened exhaust seats for better durability with unleaded fuel, and a 5-angle competition valve job on the intake, with a full radius on the exhaust valve. These heads also accept most stock bolt-on components. The result of three decades of cylinder head development, Iron Eagle heads incorporate features that were previously available only in expensive aluminum cylinder heads. Dart designed the Iron Eagle heads for street performance, bracket racing, oval track competition, and high-performance marine use. five different intake ports are offered: 165cc, 180cc, 200cc, 215cc, and 230cc, that cover virtually every engine application. Dart Iron Eagle heads have standard features you don't get in other factory and aftermarket cast-iron cylinder heads. Long-wearing bronze valve guides (except S/S), multi-angle intake valve seats, and hardened and radiused exhaust seats are standard.
Pro 1 200cc Aluminum SBC Cylinder Head
There's a Pro 1 head for virtually every small-block engine. Dart offers a choice of four intake runner sizes (180 cc, 200 cc, 215 cc, and 230 cc), two chamber volumes (64 cc and 72 cc), five valve diameters, and straight or angled spark plugs. Dart has improved the original small-block design with extra-thick decks and high-capacity water jackets that increase reliability in high-performance applications. Hardened exhaust seats and long-lasting mag-bronze valve guides significantly extend cylinder head life. Pro 1 heads are engineered for easy installation.
These heads work with standard small-block pistons, headers, and valvetrain components, and are bolt-on replacements for most conventional 23 heads.