Chevy released the Mark IV big-block or "Rat" in 1965 to replace its "W"-series motors. This new engine featured (among other things) new valve placement and combustion chamber design to increase volumetric efficiency at higher rpm. Starting with 396ci in 1965, Chevy eventually went up to 454 in 1970. In between, you could get a 402 and even an all-aluminum 427 with a single four-barrel that was grossly underrated at 430hp. The kings of the street in the power department were the 1966 427 L72 that was originally rated at 450 hp (it was knocked down to 425 later in the model year) and the LS-6 454 of 1970 that was also rated at 450 hp. Then came the GM Performance Parts crate engines, like the 502/502 and then the monster 572 in 2003 that laid down 720 asphalt-destroying horsepower.
Today, the world is your oyster when it comes to Rat-engine power enhancers, which makes surpassing the older hp ratings a lot easier. The aftermarket has embraced the big-block and you can get everything from a set of lifters to a stroker crank. We used our connections to find out what the newest products on the market are so you don't have to-you can thank us later.
Aerohead Racing offers a set of fully assembled cast iron cylinder heads for the 454/502 big-block engines. Utilizing new GM castings, these heads feature rectangular intake ports, machined 7/16 studs and guide plates, 2.190 or 2.250x1.880 stainless steel valves, 119cc open combustion chamber, 310cc intake runners, hardened exhaust seats, 0.580-lift springs, 7-degree locks and chrome-moly retainers.
ARP has just released two new bullet-nose head stud kits for World Products cylinder heads. ARP has added 23 new part numbers for World Products customers over the years. These kits include all necessary 8740 studs, chrome-moly washers and 12 pt. nuts for the application, and a 1/2-ounce pack of ARP Ultra-Torque fastener assembly lubricant. All ARP 8740 studs are centerless ground, heat treated prior to thread rolling and machining, and are nominally rated at 200,000 psi. Most studs are broached to ease installation and removal.
Callies just introduced the Magnum Series III crankshaft for Rats. The Series III features the company's new dual-arc leading edges that are designed to not only reduce crankcase windage, but lead to lower manufacturing costs, saving you money. Stroke ranges are available from 3.500 to 5.500 to accommodate an array of cubic inch configurations. Also be on the lookout for the Callies Ultra connecting rods coming soon.
Callies Performance Products
The Comp Cams new Elite Race solid roller lifters are built to withstand even the most demanding racing conditions. They feature an REM-polished 8620 alloy body with a modular design that allows the pushrod seat inserts to be swapped for centered, left or right offsets. This patent-pending design also includes oversized (0.400) axles that are dual-pinned with a small gap in between for better oiling, along with center and top axle oil inlets for lubrication through the axle, directly to the needles. Finally, the captured link bars offer maximum control and durability for race and high rpm applications.
Dart's new CNC-machined Pro 2 aluminum cylinder heads with 380cc intake ports are just what the doctor ordered for large displacement big-block Chevrolet racing engines. With the growing popularity of Top Sportsman, Quick 32, and other go-fast classes, engine displacements have been steadily escalating. Dart's new 380cc Pro 2 heads have the airflow capacity to feed these massive motors. Based on Dart's Race series 355-T6 aluminum head casting, the new Pro 2 head's 380cc intake runners are paired with 144cc exhaust ports. Intake valves are 2.300-inches, and the exhausts measure 1.880. Brass head bolt tubes are inserted between adjacent intake runners to allow the ports to be widened.
With the original 454 and 502 forgings no longer available, Diamond has not only introduced replacement forged pistons in a variety of bore sizes for both engines, but also increased the compression ratios from their original ratings. These new pistons accommodate 2.190 intake and 1.880 exhaust valves and are supplied with 8620 chrome-moly piston pins and appropriate rings.
Doug's Headers now offers a tuned long tube header that is specifically designed to fit tall-deck big-block Chevrolet V-8 engines like the 572 in '67-69 Camaros and '68-72 Novas. These headers are built with 3/8-inch thick flanges, 16-gauge tubing, 21/8-inch primaries, 31/2-inch collectors, and are designed for maximum allowable ground clearance. They come standard with a metallic ceramic coating, reducers, 1,100-degree-rated gaskets and premium installation hardware. The headers can also be ordered uncoated if you so chose.
Eagle has several new products to push the limits of your standard-deck or tall-deck height 454 or 502 block. The rotating assemblies utilizing a 43/8-inch stroke crankshaft net you a 511 using a 454 with +0.060 pistons. In a 4.500 bore 502 block, you will have 557. Eagle also has 4.750-inch stroke cranks and assemblies for tall-deck 454 and 502 blocks. Now you can build that 632 "mountain motor" economically for serious power. As with all Eagle competition assemblies, the crank is forged 4340 chromoly steel. Rods are Eagle's forged 4340 chrome-moly steel H-beam. Pistons are forged 4032 Mahle featuring skirt and ring land coatings. Rings are plasma moly file-fit, and bearings are Clevite77 "H" series. Internally balancing is available and optional ESP Armor will provide a limited one-year warranty.
Eagle Specialty Products
Eddie Motorsports' new valve covers are specifically designed to work on big-block engines that need clearance for stud girdles and roller rockers. They are cast from high quality aluminum and machine finished across the face to insure a consistent surface for polishing. They are also available Fusioncoated by special order. Each set includes an oil fill hole and cap on one cover and stainless steel bolts and washers.
The new Edelbrock RPM Xtreme cylinder heads for 427-572 big-blocks strive to provide race-level performance in a streetable design envelope. CNC machined runners and combustion chambers achieve flow numbers nearly on par with the Victor series professional race head, while maintaining compatibility with off-the-shelf or even stock components, including headers, pistons and rocker arms. The deck has been rolled 1.5-degrees to improve the intake valve angle and consequently port velocity, while ensuring that the 2.250 (oval)/2.300 (rect.) intake and 1.880 exhaust valves will still clear the factory valve relief. The exhaust flange has been raised less than 1/8-inch to improve flow around the short turn without causing conflicts with off-the-shelf 2-inch primary tube headers designed to work with stock heads.
Holley HP EFI for standard and tall-deck, oval port and rectangle port big-blocks will get you to the cruise or race track in no time. The 1,000 cfm throttle bodies to feed up to 750-hp and the 2,000 cfm throttle bodies feed up to 1,100hp. The new HP ECUs come with four inputs and outputs and can control boost, progressive nitrous, water or methanol injection, timing retards and more. Plus the HP ECUs have self-learning fuel strategies, so you don't have to be a tuning wizard to use them. The system includes an intake manifold, billet throttle body, ECU, wiring harness, fuel rails, and related small parts. Fuel pump and injectors are available separately to fit your requirements.
Holley Performance Products
If you are looking to use a Quadrajet carb to feed your 396, 402, 427, 454, 496, or 502, then check out this ready to go unit from Jet. This carb is designed for big-block motors with a dual-plane intake, headers, 8.5-9.5:1 compression ratio, and mild ported or aftermarket heads. Jet recommends using a cam with these specs, duration @50 0.050 min 210 degrees, max 240 degrees and lobe separation angle of 110-114 degrees to make best use of the carb. It comes with a one year warranty.
Jet Performance Products
Kenne Bell has introduced a new Boost-A-Pump, which increases the flow of any eletric fuel pump up to 50-percent thereby eliminating the need for larger and more expensive pumps and fuel lines. This is the same basic unit used with all Kenne Bell supercharger kits. It's easy to install and works on any GM electric pump.
Moroso introduces a new steel, wet sump, 6.5-quart oil pan for street/strip big-blocks. The pan was designed with a sump that has flat sides to alleviate header clearance problems with some exhaust header brands. The flat sides eliminate the need to change headers or perform fabrication work to the kicked out sump of the oil pan. Based on a stroker oil pan core that will accommodate a 4.75-inch stroke with most steel rods and 4.5-inch stroke with most aluminum rods. It also features a crank scraper, uni-directional windage tray, trap baffling and an anti-climb baffle for oil control under hard acceleration and deceleration.
Moroso Performance Products
The APS starter from MSD features all new components beginning with a three horsepower motor. With a 4.4:1 reduction gear set, it delivers enough torque for high-compression racing engines. Inside the downsized housing you'll find a balanced armature that receives guidance by two ball bearings for smooth engagement. Another handy feature is that the billet-mounting block can be rotated in different positions to help clear oil pans and suspension parts. Also, the starter is powder coated MSD red and will stay looking good, even though it's underneath your car.
If you're building a Rat that's really big, you'll need cylinder heads that can provide enough airflow. Patriot Performance has introduced its 320 and 360 heads to address the needs of those who want to make serious horsepower. Both heads are cast from 356 T-5 aluminum. The 320cc heads come with either a 2.25- or 2.300-inch intake valve, while the 360s can be ordered with only the 2.300-inch intake valve. Both heads utilize a 1.880-inch exhaust valve. The 320 can be set up with springs for either a hydraulic roller cam or a solid roller, while the 360 is set up with a 0.800-inch solid roller spring only. According to the folks at Patriot, the 320 can be used on engines up to 530 ci and capable of supporting 775 hp, while the 360s are designed for engines 530 cubes or larger and can support over 800 ponies.
Performance Distributors has applied its years of ignition knowledge to the popular ZZ series of crate engines with their new ZZ Crate Engine D.U.I. Distributor. This new D.U.I. (Davis Unified Ignition) is specifically designed for the ZZ-454, and the ZZ-502. This drop in distributor has the exact advance curve and Melonized distributor gear GM recommends for these engines. The distributor comes complete, including the dependable Street/Strip D.U.I. Coil and Dyna-Module, which allow you to open up your plug gaps to 0.050 to 0.055 inches, burning your fuel more completely.
The newest distributor in the Pertronix line is this plug-and-play billet unit that features the patented Ignitor III electronic ignition module. The housing is CNC machined from 6061 T-6 aluminum and then polished to a high luster. Additional features include a simple two wire hook up with no external components required, tempered 0.500-inch diameter shaft with low torsion displacement; an upper ball bearing and lower self-lubricating oil-impregnated copper powder metal bushing and a heat-treated gear. The distributors come with a factory-set performance curve, a mechanical advance limiting adjustment, and small diameter, high dielectric strength cap and rotor for installations with tight firewall clearance.
Procomp Motorsport's new big-block aluminum cylinder heads feature a 320cc intake runner with a 115cc combustion chamber volume, 2.250 intake and 1.880 exhaust valve package. Features include stainless steel, one-piece swirl-polished undercut valves, high-performance valve springs (flat tappet or roller), chromemoly retainers, 10-degree valve locks, screw in studs and guide plates. Procomp heads come ready to install right out of the and will support up to 800hp.
Proform's race-series 650 to 1,050 cfm carbs feature a high-flow aluminum main body, adjustable screw-in air bleeds, high-rate air-flow section design, solid billet construction, Teflon coated throttle shafts, sight glass windows and a billet throttle base plate. These carbs use standard service and tuning components. High performance down-leg boosters (except 650), timed and full vacuum tubes for accessories and tuning, power valve blowout protection and slip-link mechanical secondary linkage are a few more features. They are ready to run right out of the box and are available with mechanical or vacuum secondaries.
Proform/Specialty Auto Parts
RHS Pro Elite 24-degree CNC-ported aluminum cylinder heads are sure to give your Rat the performance it deserves. They are available with either a 339cc or 376cc intake and 135cc exhaust runners, with CNC-ported 121cc combustion chambers. The multi-angle intake and radiused exhaust valve seats offer improved airflow and increased hp straight from the factory, while the extra-thick deck surface allows angle milling for compression and increased rigidity. The 24-degree aluminum cylinder heads were designed for use with hardcore big-block drag and marine racing applications.
Ross has introduced 10 new part numbers for forged big-block pistons intended for supercharged and turbocharged applications. Forged out of premium 2618 T-61 aluminum, they feature dual pin oilers, second-land accumulator grooves, and a flattop head design with a single valve relief. They are available in bore sizes from 4.280 to 4.530 and strokes from 4.000 to 4.250. Compression ratio varies upon application from 7.0 to 8.5:1. Even though these forgings are extremely strong, they are very lightweight, ranging from 526 grams to 706 grams. They come complete with pin locks and 5115 Series straight wall pins.
Ross Racing Pistons
Summit Racing dual-quad carb/intake Pro Packs bring together high-quality, name-brand components for one low price. The experts at Summit Racing specially match the components to deliver increased horsepower and improved drivability. You get an Edelbrock C-66 O polished aluminum dual-quad intake, two Edelbrock Performer 600cfm carburetors, Edelbrock Elite series air cleaner, throttle linkage, intake and valve cover gaskets, and carburetor studs.
Summit Racing Equipment
This all-new design Merlin X aluminum head from World's engineering team combines flow characteristics common to expensive race-only heads with exotic splayed valve setups, yet these are designed to accept up to 2.350 and 1.880 valves, as well as "standard" Mark IV intake systems. This has been accomplished through "rolling" the head to a 16-degree valve angle, designing highly efficient intake and exhaust ports and using a special 90cc combustion chamber. You'll probably need to get a set of pistons that take advantage of the chamber design, but other than that you can use most of everything from a standard big-block.