Cylinder Head - Light Headed - Mopar Muscle Magazine

When considering engine performance, if anything has been a game changer, it is the advancement in cylinder heads. Back in the '60s and '70s, and even the '80s, the average street machine's engine typically wore the same iron heads the engine left the factory with. In those days, the typical hot-street cylinder heads might have received a three-angle valve job and a set of springs to match a hotter cam. Sure, there were some serious performance cylinder heads, like the famous iron W2 small-block units from Direct Connection, but the vast majority of street engines ran stock production heads. These days, aftermarket cylinder head choices are broader than ever, and given the potential performance gains versus the cost, they offer an excellent value compared to rebuilding old factory iron. Aftermarket cylinder heads are available in aluminum and iron construction. While there are iron heads that definitely offer a performance advantage over the factory units, we will save that discussion for another day. Our focus here is on the street/strip style aluminum aftermarket heads that will bolt onto a factory 59-degree engine block.

When considering an upgrade in cylinder heads, it is important to have clearly defined goals in mind. If the engine is going to be a mildly modified stock displacement street cruiser, there is little point in going beyond an entry level aftermarket head, such as the Edelbrock or Mopar Performance units. From that entry level point, the scale moves up in cost, complexity, and ultimately power potential. Differences such as offset rocker valve trains, W2 style intake and exhaust patterns, or additional porting can easily double the cost of a cylinder head conversion. Depending upon your budget and goals, those feature quickly become desirable or necessary. Ultimately, it is going to be cylinder head airflow that limits rpm and horsepower potential. When dealing with today's big-inch stroker small-blocks in particular, cylinder head airflow becomes even more critical in getting the most from the useful rpm potential of the engine.

Brodix / Koffel

Koffel's B1BA cylinder head is one of those parts that seem to fly just under the radar screen, but it is definitely worth some attention. Cast by Brodix, the B1BA cylinder head was intended to be a straightforward, bolt-on upgrade for a stock LA-style head. The B1BA retains the stock, non-offset valvetrain utilizing B1BA specific rocker stands. The heads also features the production bolt pattern on the intake and exhaust flanges, retaining compatibility with common LA-Series parts. The departures from the stock layout include raised exhaust ports and relocated spark plugs, requiring header modifications in some installations. Breathing through 2.08-inch intake valves, the as-cast flow is better than any other as-cast stock configuration head. The potential only goes up from there with porting, with Brodix reporting 303 cfm @ 0.700 for the ported B1BA.

Koffel also offers the B1BA MC cylinder heads, which feature relocated valves for a major increase in valve size. The B1BA MC has unmachined pushrod slots, requires a race-style shaft mounted rocker system, and uses a W5 or W7 intake manifold. The exhaust face is also left blank so that a W5, W7, or stock exhaust pattern can be drilled. These B1BA MC heads can be considered specialty race heads outside of our focus here.

We would put the power potential of the B1BA in the 450-500 horsepower range for an as-cast head, depending upon the seriousness of the effort, while fully ported we would expect to be around the 600 horsepower mark with a serious small-block stroker combo.

Head: B1BA
Intake Port Volume: 195cc
Chamber Volume: 65cc
Intake Flow: 269 @ 0.700 As-Cast
Exhaust Flow: 198 @ 0.700 As-Cast
Intake Valve Size: 2.08
Exhaust Valve Size: 1.60
Rockers: Standard LA-Series
Bolt Pattern Int/Exh: Standard LA-Series

Dr J's Performance

The AirWolf cylinder heads from Dr J's Performance are designed to take the conventional bolt-on cylinder head configuration to its airflow and performance limits. The head features a standard, non-offset valvetrain, as well as stock LA-Series bolt patterns on the intake, exhaust, and deck. The heads are only offered in fully CNC ported form, with unique castings to accept the developed ports. The intake volume stretches the standard configuration to a whopping 220cc, with peak intake flow in the mid 320s through a 2.08-inch valve, with equally impressive exhaust flow maxing out at the mid 240s utilizing a 1.60-inch exhaust valve dimension.

Power potential of the AirWolf is impressive, as we have seen 630-plus horsepower with a moderate 408 stroker combination, and expect the upper range potential to crowd the 700 horsepower mark in an all-out race small-block. By keeping the stock architecture, the AirWolf offers a cost-effective approach to serious small-block power.

Head: AirWolf Mopar 220 CNC
Intake Port Volume: 220cc
Chamber Volume: 60-70cc
Intake Flow: 316 @ 0.700 Full CNC
Exhaust Flow: 236 @ 0.700 Full CNC
Intake Valve Size: 2.08
Exhaust Valve Size: 1.60
Rockers: Standard LA-Series
Bolt Pattern Int/Exh: Standard LA-Series

Edelbrock

If any aftermarket cylinder heads redefined the small-block Mopar, it is the Edelbrock RPM offerings. Available in both LA and Magnum Series, the idea was to build a direct replacement aluminum cylinder head with improved power as the goal. With the moderate cost of the conversion, these heads have become extremely popular as an upgrade over OEM iron heads. Featuring the popular 2.02/1.60-inch valve sizes, the heads retain the OEM intake, exhaust, and rocker configuration. This means that these parts can be carried over when retrofitting from a stock head, a big cost savings if you already have a performance intake, valvetrain, and headers. The Magnum version retrofits the rocker arrangement from the stock pedestal mount to a small-block Chevy stud mounted arrangement, for a virtually unlimited selection in aftermarket rockers.

Edelbrock heads have become a favorite upgrade for the small-block Mopar, offering a significant weight reduction, good flow, and a straight forward installation. The heads come in both LA-Series and Magnum versions. Edelbrock’s Magnum heads stray from the straight replacement approach by their stud-mount rocker configuration, which accepts common Chevy small-block aftermarket rockers. This substantially increases the number or rocker options.

Out of the box, peak intake flow is in the mid 250 cfm, with max-ported versions typically falling in the upper 200 range. The heads have an easy bolt-on 400-plus horsepower potential on a mild street combination, and can support over 500 horsepower in ported form. For an all-out race small-block, the RPM heads definitely have their limitations, but for a nice street or moderate performance engine, the Edelbrock cylinder heads are a home run.

Head: Performer RPM LA
Intake Port Volume: 171cc
Chamber Volume: 63cc (65cc relieved optional)
Intake Flow: 251 @ 0.600 As-Cast
Exhaust Flow: 190 @ 0.600 As-Cast
Intake Valve Size: 2.02
Exhaust Valve Size: 1.60
Rockers: Standard LA-Series
Bolt Pattern Int/Exh: Standard LA-Series
Bolt Pattern Deck: Standard 10-Bolt

Head: Performer RPM Magnum
Intake Port Volume: 176cc
Chamber Volume: 58cc
Intake Flow: 260 @ 0.600 As-Cast
Exhaust Flow: 190 @ 0.600 As-Cast
Intake Valve Size: 2.02
Exhaust Valve Size: 1.60
Rockers: Chevy SB Stud Mount
Bolt Pattern Int/Exh: Magnum Vertical

Indy Cylinder Head

Indy's T/A heads are a proprietary modification of the Edelbrock cylinder head castings by Indy Cylinder Head. The concept here was to take what is already a popular and excellent quality casting, and address some key issues to raise the ultimate power potential of the heads. To accomplish this, the heads are provided to Indy in as semi-machined castings, allowing for the unique Indy T/A configuration. The primary modification is to alter the intake pushrod clearance location away from the intake ports, which removes the primary restriction on port width. This allows Indy to widen the runner at the pushrod restriction by 0.190-inch compared to a standard Edelbrock LA head.

The angled pushrods require an offset rocker arrangement. Indy relocates the rocker mounts for longer 440-style Indy offset rockers, upgrading the fastener size and alleviating the restricted spring clearance found in a standard small-block Mopar head. The heads feature larger valves than the stock Edelbrock, with 2.05-inch intakes. While the Indy T/A utilizes an offset rocker arrangement, it retains the OEM LA-Series intake and exhaust bolt patterns, for compatibility with standard intake manifolds and exhaust headers. The heads are an excellent choice for a hot street or strip stroker looking for more power potential than a standard-style head, or a smaller displacement engine looking for outright high-rpm power. With full porting, the right combination should top the 600hp mark.

Moving up to make power on a more serious level takes moving up to a more serious cylinder head configuration. The 360-1 and 360-2 cylinder heads take the top-end combination to race level performance, with essentially the Mopar W-series style mods. Here, the first thing we find is the offset rocker arrangement, using Indy's big-block style rockers with 0.800-inch offset on the intake. This gives the clearance for the large valvesprings required in a serious engine, and also allows larger, unobstructed intake ports. The 360-1 features rectangular intake ports, while the 360-2 carries a smaller oval port. These cylinder heads are fitted with oversized 2.100/1.625-inch valves and have the W-2 style intake manifold bolt pattern and both the standard and W-2 exhaust bolt patterns. Additionally, these heads have the extra bolt provisions for the race-block 18-bolt deck pattern and are still compatible with the factory 10-bolt pattern.

If you are looking to take power to the next level, the Indy cylinder heads have what it takes. The fully CNC ported versions from Indy offer the required flow, and the race-derived cylinder head configuration takes care of the rest. Indy puts the power capability of the 360-1 at 750 horsepower, and at 700 for the 360-2 oval port. If you are building a serious Mopar small-block, the Indy 360 heads are definitely designed to take care of business.

Head: Indy T/A
Intake Port Volume: 175cc As Cast
Chamber Volume: 63cc
Intake Flow: 275 @ 0.600 As-Cast (306 @ 0.700 Full Indy Porting)
Exhaust Flow: 182 @ 0.700 As-Cast (197 @ 0.700 Full Indy Porting)
Intake Valve Size: 2.050
Exhaust Valve Size: 1.600
Rockers: Indy Offset, Intake
Bolt Pattern Intake: Standard LA-Series
Bolt Pattern Exhaust: Standard LA-Series
Bolt Pattern Deck: Standard LA-Series

Head: Indy 360-2 (360-2 CNC Optional)
Intake Port Volume: 180cc (230cc CNC)
Chamber Volume: 63cc (65cc CNC)
Intake Flow: 252 @ 0.700 As-Cast (322 @ 0.700 CNC)
Exhaust Flow: 189 @ 0.700 As-Cast (255 @ 0.700 CNC)
Intake Valve Size: 2.100
Exhaust Valve Size: 1.650
Rockers: 0.800-Inch Indy Offset Intake or Jesel
Bolt Pattern Intake: W-2 Pattern
Bolt Pattern Exhaust: Standard LA-Series and W-2
Bolt Pattern Deck: Provisions For 18-bolt Pattern Included

Head: Indy 360-1 (360-1 CNC Optional)
Intake Port Volume: 210cc (245cc CNC)
Chamber Volume: 63cc (65cc CNC)
Intake Flow: 280 @ 0.700 As-Cast (330 @ 0.700 CNC)
Exhaust Flow: 189 @ 0.700 As-Cast (255 @ 0.700 CNC)
Intake Valve Size: 2.100
Exhaust Valve Size: 1.650
Rockers: 0.800-Inch Indy Offset Intake or Jesel
Bolt Pattern Intake: W-2 Pattern
Bolt Pattern Exhaust: Standard LA-Series and W-2
Bolt Pattern Deck: Provisions For 18-bolt Pattern Included

Mopar Performance

Mopar Performance's entry into the aluminum small-block cylinder head market starts with the Aluminum Magnum and the Aluminum Commando LA-Series cylinder heads. These heads are based on the Edelbrock castings, and in terms of the relative configurations, they are virtually identical to the Edelbrock RPM offerings. As with the Edelbrock heads, the Mopar versions make a nice street performance head as a bolt-on 400-plus horsepower assembly in a mild small-block, and max-out in the mid 500s with competent full porting.

The Super Commando cylinder head is also based on the Edelbrock castings; however, these heads feature larger intake valves and the offset rocker modification, allowing the intake port to be wider and unencumbered. As with the Indy T/A, this modification allows more intake port cross-sectional area and an improvement in intake port flow potential. The Super Commando utilizes a unique rocker offset and is serviced by Mopar #P5153995 rocker arms, though the availability of these corresponding rockers has been sporadic.

Mopar Performance offers Aluminum Commando heads for the LA-Series and the Aluminum Magnum for the later Magnum engines. The features are identical to Edelbrock’s offerings. The Mopar Performance Super Commando ups the ante on the Commando heads with an offset rocker arrangement allowing for a wider intake port. This is the cylinder head used on the Mopar 440 small-block crate engine.

In terms of additional Aluminum Small Block cylinder heads from Mopar Performance, the company does offer a range of full-on race heads in their W-9 and P5 series. These heads are designed for use on the Mopar Performance race blocks. Although it is possible to utilize these heads in an all-out build, they and are outside the realm of the street/strip cylinder heads we are detailing here.

Head: Mopar Commando LA
Intake Port Volume: 171cc
Chamber Volume: 63cc (65cc relieved optional)
Intake Flow: 251 @ 0.600 As-Cast
Exhaust Flow: 190 @ 0.600 As-Cast
Intake Valve Size: 2.02
Exhaust Valve Size: 1.60
Rockers: Standard LA-Series
Bolt Pattern Int/Exh: Standard LA-Series
Bolt Pattern Deck: Standard 10-Bolt

Head: Mopar Aluminum Magnum
Intake Port Volume: 176cc
Chamber Volume: 58cc
Intake Flow: 260 @ 0.600 As-Cast
Exhaust Flow: 190 @ 0.600 As-Cast
Intake Valve Size: 2.02
Exhaust Valve Size: 1.60
Rockers: Chevy SB Stud Mount
Bolt Pattern Int/Exh: Magnum Vertical

Head: Mopar Super Commando
Intake Port Volume: 175cc
Chamber Volume: 63cc
Intake Flow: 265 @ 0.700 As-Cast
Exhaust Flow: 190 @ 0.700 As-Cast
Intake Valve Size: 2.055
Exhaust Valve Size: 1.600
Rockers: MP Offset Rocker Arm Set P5153995
Bolt Pattern Intake: Standard LA
Bolt Pattern Exhaust: Standard LA-Series mm

---

Sources

Brodix
479/394-1075 ' www.brodix.com

Dr J's Performance
714/808-9780 ' www.j-performance.com

Edelbrock
800/416-8628 ' www.edelbrock.com

Indy Cylinder Head
317/862-3724 ' www.indyheads.com

Koffel's Place
419/443-4410 ' www.b1heads.com

Mopar Performance
www.mopar.com