This chapter covers any cylinder head that uses an intake or exhaust flange that is not compatible or consistent with OEM patterns. To put it in more simple terms, a typical set of LSX headers and exhaust manifolds do not bolt up and neither do any LSX intake manifolds.
This Tech Tip is From the Full Book, HIGH-PERFORMANCE GM LS-SERIES CYLINDER HEAD GUIDE. For a comprehensive guide on this entire subject you can visit this link:
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A proprietary intake or exhaust flange, which typically comes with the head, must be used to create a custom intake manifold and headers. Some companies even offer their own cast intake manifold, which limits fabrication to the headers.
Liberating from factory-based designs creates some out-of-the-box thinking with no compromises, and the ultimate performance. The only downside is cost.
All Pro/West Coast Cylinder Heads
West Coast’s program for the All Pro LSW-2 is a game-changer. No longer do you need a canted valve to produce more than 440 cfm. These heads are based on the original LS7 design; however, a proprietary port location (C5R bolt pattern) neccessitates All Pro’s cast two-piece intake manifold or a fabricated sheet-metal piece. The exhaust ports are also proprietary and have an 8-bolt flange. Jesel and T&D both make rocker system to accommodate this unique, 12-degree (in-line) head. West Coast has two runner and chamber programs. The larger 330-cc head continues to increase in flow as it hits .900-inch lift with 446.3 cfm. This head is designed specifically for all-out, naturally aspirated builds (hence the small chamber). The 310-cc port leaves more material for greater stability on forced-induction builds while also responding well at high lift, hitting 422.6 cfm at .850-inch lift using a 2.20-inch valve. These heads also have a 65-cc chamber and 116-cc exhaust runner. Both heads have plenty of clearance for 1/2-inch pushrods and utilize the regular LS valve cover pattern. As with all heads in this section, a large (4.125-inch) bore is required. Prices start at $3,290. (Photos Courtesy West Coast Cylinder Heads)
LS Hemi Chevy
Pro Mods have been running Hemis for decades, so it’s no wonder Nick Arias, Jr. developed a casting to adapt this design to an LS engine. These heads were designed for big-power drag racing applications to take advantage of 400-plus cfm. Right out of the box these heads flow 380 (intake) and 268 (exhaust) cfm. The chamber is one of the largest attractions with this head; boost lovers can utilize the large, full-hemisphere. Up to a 1.650-inch-diameter valvespring is accepted. Special pushrods, ARP head studs, investment cast 4340 roller-tip rockers, cast-aluminum valve covers, Cometic head gaskets, oil drain-back line, header flanges (and hardware), and intake/exhaust gaskets are included for $9,975. Hemi pistons, intake manifold, and oil drain bungs are also required. (Photos Courtesy Arias)
Believe it or not, Chevrolet Performance (formerly GM Performance Parts) was a little late to the game in terms of aftermarket product development for the Gen III/IV. But as this market took off, GM was quick to make up ground. Today it boasts an impressive catalogue from budget to high-performance street and full-on (drag and circle track) racing parts. Its resources for testing and development is unparalleled, making it easy to achieve such high-quality parts. Yet the ability to cast its own heads, and in large quantities, allows a low price point. The LSX line was designed with help from not only GM’s talented engineering team, but drag racing legends such as Warren Johnson and LS industry insiders.
Chevrolet Performance C5R
These are the first race heads ever created for an LS engine, developed for the Corvette C5R Racing program. The raised rectangular port later inspired the LS7; however, no factory intake manifold bolts up to it. Most opt for a custom sheet-metal intake; however, many have modified an SB2 to work. These heads combine high flow with excellent velocity, and when ported properly they can support more than 1,000 hp (and 9,000 rpm) naturally aspirated. The runners and chambers come “as cast” and rough, requiring professional machining; there are no valve seats or guides. The exhaust port is standard LS1, so any regular LS exhaust flange bolts right up. The 11-degree valve angle, however, requires aftermarket rocker arms. Retail price is around $1,978 from Chevrolet Performance dealers such as Scoggin-Dickey.
The LSXDR heads were the perfect follow-up to releasing the short- and tall-deck LSX block by Chevrolet Performance. Developed specifically for drag racers pushing the limits, the DR head has proven to be a good match for high boost and nitrous while still utilizing inline 11-degree valves like its C5R predecessor. The small chambers make these heads particularly valuable on a nitrous car, which is probably why they have high 6-second and low 7-second passes to their credit. Just like the C5R, a 4.125-inch bore is required. The intake runners are raised and the exhaust ports are spread, so the head requires proprietary intake manifolds and flanges as well as rocker arms. The CNC program, done by Livernois, is said to be capable of 900 hp on the engine alone (thanks to its incredible 424.5 cfm at .900-inch lift). Retail price is around $1,600 each (bare).
The “CT” stands for Circle Track, and these heads bear plenty of resemblance to their DR cousin. Derived from the C5R, the CT head also uses the same 10-mm raised intake runner and spread-port exhaust pattern (proprietary flanges required). The smaller runners enhance velocity and make the heads suitable for circle-track racing. Special 356-T6 alloy ensures longevity, and the combination of a 5/8-inch-thick deck and LSX-style 6-head-bolts-per-cylinder ensures plenty of clamping. These heads (like the DR) are available prior to machining, and a complementing intake manifold and rocker system is available through Chevrolet Performance. Just like the DR heads, these go for around $1,600 each (bare).
LSR/Race Flow Development
Edelbrock’s Victor LSR is one of only two canted-valve heads on the market, and with more testing these could be the heads to beat. Race Flow Development has several different programs with different valves (2.20- to 2.26-inch intake) and runner cross-section to accommodate various combinations. RFD says it has three to five different variations on the LSR’s intake runner, but only two on the exhaust runner (usually the smaller is used for naturally aspirated, and the larger for forced induction). There are another two or three different chambers; however, the heads can be milled as needed to achieve the desired compression. A custom intake manifold is required for the proprietary runner shape and location, as with the exhaust and rocker arms. These heads have made more than 1,000 hp naturally aspirated with 2.25- and 1.6-inch valves that help flow 450 and 298 cfm, though they are capable of more than 465 cfm. Prices vary from $4,800 bare to $7,200 assembled. (Photos Courtesy Race Flow Development)
Mozez Canted Valve
Easily one of the highest-flowing heads out there, Mast’s canted-valve head is used by the fastest nitrous LSX cars and even a few turbo cars. A 10-degree valve angle with a 4-degree cant on the intake and a 7-degree angle on the exhaust with a 2.5-degree cant make the runners a straight path in and out. The raised intake runners have a perfectly oval shape, which requires either Mast’s 2-piece intake or a custom sheet-metal piece. Only SB2 valve covers, or Mast’s cast racing covers are compatible. A 4.125-inch-or-larger bore is required. Retail price is $2,500 each (bare).
Written by Dave Grasso and Posted with Permission of CarTechBooks
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