Aluminum Chevy Big Block Engine Build

By Jeff Huneycutt – Images by the Author

In the 1960s, many of Lola Cars’ most successful racing machines were powered by Chevrolet small- and big-block V-8 engines. Company founder Eric Broadley recognized early on the advantages of building his lightweight British racers around potent, reliable American V-8s. Despite being a relatively young constructor, Lola quickly earned a winning reputation, thanks in large part to the performance of its Chevy-powered cars.

002 aluminum big block chevy build — The block is a 10.2-inch tall-deck aluminum block from Brodix that cuts over 50 pounds versus a cast-iron block. This particular block has been ordered with a raised cam tunnel and a 60mm cam bore. Large cam bearings can be difficult to drive in and keep square, so Prestige’s Darin Beaver pressed each in with a special tool.

The Lola T70, introduced in 1965, was designed from the outset to accept large American V-8 power. In 1966, driving a Chevy-powered T70 Spyder, John Surtees captured the inaugural Can-Am championship, winning all but one race that season. Lola T70s claimed five of the six Can-Am races that year in a dominant showing against rivals like McLaren and Chaparral. These machines also proved their endurance capabilities; a Team Penske Lola T70 Mk3B, backed by a 5.0L Chevrolet, scored a celebrated overall victory at the 1969 24 Hours of Daytona. Throughout the late ’60s, Chevy-powered Lolas regularly challenged factory teams, such as Porsche, Ferrari, and Ford, underscoring Lola’s ability to blend British engineering with American horsepower.

003 aluminum big block chevy build — The crankshaft is a forging from Callies with 4.375 inches of stroke.

By the end of the 1960s, the success of Chevy-powered Lola cars had firmly entrenched the company among racing’s elite constructors. Although they did experience greater success in the U.S. than Europe, the big, high-compression engines struggled with the poorer fuels over there but were allowed to burn Avgas in the States. Models like the thundering Lola T70 sports racer and the versatile Lola T142 formula car demonstrated Lola’s knack for pairing British chassis ingenuity with American V-8 muscle. Plus, the cars were just beautiful. There’s something magical about the silhouettes in sports cars from the ’60s.

004 aluminum big block chevy build — To squeeze that much stroke in the block and also keep a nice, long connecting rod for an optimal rod/stroke ratio, Prestige went with a tall-deck block. You’ll notice that they are also using one of Moroso’s billet internal oil pumps for optimal oil pressure even under the harshest conditions.

Of course, any original Lola T70 MkIII you come across will probably be in an automotive museum but just like with the Shelby Cobra there is a healthy replica industry that can replicate the look and feel of these beautiful cars without the million-dollar budget it would take to acquire an original. That’s exactly what this big-block engine build is all about. Prestige Motorsports, out of Concord, North Carolina, got the call to build an engine for a customer’s 1969 Lola T70 Mk3B replica build from Replica Race Cars out of Fraser, Michigan.

005 aluminum big block chevy build — Speaking of Moroso, they also produced this fully fabricated road-race, wet-sump oil pan with a big 8-quart capacity and a fully segmented windage tray to help move excess oil quickly and efficiently away from the crankshaft and into the sump.

Obviously, going into a car that celebrates the heritage of one of the great race cars from the golden age of sports car racing the engine could be no lightweight when it came to horsepower. But it also absolutely had to be a lightweight when it came to … weight. Even if it made tons of horsepower, a cast-iron pig that would make the Lola wallow through the turns just wasn’t acceptable.

006 aluminum big block chevy build — Combined with the 4.375-inch stroke, the custom pistons from JE are 4.600 inches in diameter to make those 582 ci. There is also a small, 10cc dome to bring the compression ratio up to 10.7:1.

So, Prestige came up with a plan to build an all-aluminum, 582ci big-block that pumps out 900 hp (on pump gas!) without adding any extra pounds to the fiberglass-bodied car. Oh, and it has to keep that old-school vibe.

007 aluminum big block chevy build — The camshaft is a steel solid roller from Comp Cams. It’s been ground with 271 degrees of duration for the intakes and 282 for the exhausts at 0.050 inch of tappet lift. Gross valve lift is 0.743 and 0.750, respectively.

The crown jewels of this build are the very tall velocity stacks from Kinsler Fuel Injection. This is not a mechanical fuel injection setup like Kinsler is famous for with Sprint Car racing but instead is an EFI port injection system with a Holley ECU controlling everything. What’s interesting is Kinsler’s engineers gave the engine builders at Prestige the heads up that running all eight velocity stacks the same height could result in dips in power along the rpm band. (Something about harmonics of air pressure/flow or something that’s way above our heads.)

008 aluminum big block chevy build — That camshaft is spun by a durable and dependable belt timing set from Jesel. Since this engine will see road miles as well as track days, Prestige will hand-fabricate a simple aluminum cover for it to keep any road debris from getting under the belt.

And that’s exactly what we saw on the engine dyno. With the 6-inch velocity stacks on the individual runner fuel injection we saw an aggressive dip in power between 4,800 and 5,100 rpm. But the guys at Prestige expected it and swapped in four 8-inch-long velocity stacks on cylinders 2, 3, 7, and 6 and ran it again. The mixed lengths of the velocity stacks not only looked cool but actually did a great job of fixing the problem. Power delivery was smooth across the pull and low-end power actually increased (although we did lose power from 5,000 to 5,700 rpm). Overall, average torque and horsepower still went up by 6.1 and 3.1, respectively. So, the mix is not only an incredible look, it’s also the better way to go in this application. That’s a win-win in our book.

Check out this story in our digital edition here.

009 aluminum big block chevy build — The 0.842-diameter lifter bores are filled with a set of solid tie-bar roller lifters from BAM.

010 aluminum big block chevy build — Like the block, the cylinder heads are also Brodix castings. They are fully CNC cut with 121cc combustion chambers and 350cc intake runners. The valves are stainless steel from Ferrea that measure out at 2.300 inches for the intakes and 1.880 for the exhausts.

011 aluminum big block chevy build — Prestige’s lead engine assembler is nicknamed simply “Senior.” He runs down the nuts on the Brodix-specific head studs and secures the heads to the block at 70 ft-lb.

012 aluminum big block chevy build — The rocker arms are ultra stiff units from Crower that keep the stock 1.7:1 ratio. They activate a set of polished valvesprings from Manley rated at approximately 700 pounds over the nose.

013 aluminum big block chevy build — Here, the Kinsler Fuel Injection intake is just going together. This will be an EFI system, and not mechanical fuel injection like these engines were outfitted with back in the day for improved tuneability with a Holley ECU handling engine controls. So, it comes with all the tricks for modern computer controls. For example, the tube running the length of the intakes on the inside isn’t a fuel rail but a balance port to harmonize intake pulses across each port.

014 aluminum big block chevy build — Senior drops on the second set of intakes.

015 aluminum big block chevy build — With the butterflies open you can see how smoothly air and fuel can flow down through the intake and into the combustion chamber.

016 aluminum big block chevy build — The custom valve covers are fabricated with integrated spring oilers. You can see the bar running along the length of the underside of the valve cover. It provides a constant jet of cooling oil to each of the valvesprings, which can be tremendously helpful during long, high-rpm track sessions.

017 aluminum big block chevy build — On the dyno we tested first with eight 6-inch velocity stacks on the stack injection intake and saw a pretty severe dip in power. Kinsler warned us ahead of time that this might happen, so we followed their advice and put on four of the stacks for longer 8-inch units. This not only fixed the dip, but everybody who has seen this setup immediately comments on the look of the mixed height stacks.

018 aluminum big block chevy build — Off the dyno and ready to go to the owner. The mixed 6- and 8-inch velocity stacks were a big winner and look fantastic. The large pipe coming out from above the valley plate is the coolant return. It pulls hot coolant from both cylinder heads at both the front and rear to reduce the chance of detonation-causing hot spots. They route to a billet four-into-one aluminum collector at the front of the engine.

019 aluminum big block chevy build — Dyno Chart

Sources
Brodix
(479) 394-1075
brodix.com
–
Callies
(419) 435-2711
callies.com
–
Comp Cams
(800) 999-0853
compcams.com
–
Crower
(619) 661-6477
crower.com
–
Holley
(866) 464-6553
holley.com
–
JE Pistons
(714) 898-9763
jepistons.com
–
Jesel Valvetrain
(732) 901-1800
jesel.com
–
Kinsler Fuel Injection
(248) 362-1145
kinsler.com
–
Manley Performance
(732) 905-3366
manleyperformance.com
–
Moroso Performance Products
(203) 453-6571
moroso.com
–
Prestige Motorsports
(704) 782-7170
prestigemoto.com
–
Race Car Replicas
(586) 329-1573
race-car-replicas.com

Aluminum Chevy Big Block Engine Build

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