700HP BIG-BLOCK 1966 CHEVROLET IMPALA SS

impala bonnet up nw

Barnaby Lester wanted a reliable, big-horsepower ride, and Dalton Automotive delivered the goods with this fine 700HP '66 Chevy Impala SS

This article on Barnaby's Impala was originally published in the May 2017 issue of Street Machine

A SUPER-clean black ’66 SS Impala packing 700hp wasn’t on Barnaby Lester’s radar. He was chuffed with the red one he had, with a stout 383ci pumping out 500hp, built by his go-to guy, Chris Dalton from Dalton Automotive in South Geelong. Having owned a string of locally built rides, he was pretty satisfied with his first American car.

chev impala rearThen this glistening black version caught his eye on eBay. It had copped a body-off-chassis rebuild a decade prior, with both the externals and interior exceeding the quality of his current ride. “So I sold off the red one and took a gamble,” Barnaby says. “I bought it from Chicago, based on one video and 60 photos. I took a punt and it paid off.” Even shipping it to Oz was a dream thanks to Darren from HTX International in Sunbury, Victoria.

chev impala frontUpon arrival it was sent straight to Dalton Automotive. “It rolled in on slicks, with NOS and some undercarriage work, so we knew it had definitely been raced,” Chris Dalton says. Up front was a 427ci big-block Chev, with Dart Pro 1 heads and an Edelbrock Victor Jr single-plane manifold.

“They advertised it as 650hp,” Barnaby says, “but Chris stuck it on the dyno and it was only about 450hp!”

chev impala profileThis disappointment set Barnaby on a quest for those missing ponies. “The first thing I did was remove the nitrous and put an 8/71 TBS supercharger on it – I’d always wanted a blown car,” he says. “And yeah, it was unreal – great fun. But I broke the motor after about a month, shearing a lobe off of the cam. Sticking a blower on a motor that’s not built for it isn’t going to last long. And I was continually worried about having the blower sticking out of the bonnet, so I sold it.”

chev impala wheelsThe Impala rolls on 15-inch Weld Vitesse RTs with huge 28x12.5 M/T Sportsman Pros tucked under the rear, attached to a strengthened 12-bolt

Barnaby instead charged Dalton Automotive with the task of building him a very well-mannered, big-horsepower, naturally aspirated ride.

chev impala front“He wanted it so he could make that power all of the time, at the hit of the throttle. It could be driven every day and not get hot,” Chris says. “We basically had to change everything: the fuel system, the electrics, the exhaust – the lot.”

They stroked the 427ci Chev to 500 cubes and packed it with tough goodies. On top, a Holley Ultra 950HP feeds the aforementioned Victor Jr manifold, port-matched to the alloy Dart Pro 1 heads with copper gaskets. A Comp Cams solid-roller takes care of lift, while below, Mahle dome-top pistons bolt to Eagle rods, swinging off an Eagle forged 4340 crank with a Pro Race balancer.

chev impala engine bayThe naturally aspirated 500ci Chev pumps out around 700hp, with 540 of those horses reaching the rear wheels

An MSD digital 6AL-2 ignition kit sparks the PULP fed by a billet Holley Black pump via half-inch lines and a Holley reg. Gases then exit via Hooker Competition headers through a twin three-inch system, with electric cut-outs for full-tote noise. The whole shootin’ match is cooled by a PWR custom radiator and a 16-inch thermo.

chev impala engineDespite the power, Barnaby says the Chev is a great cruiser. “You can cruise in it no problem; I could drive it every day, but it would cost me an arm and a leg in fuel”

Behind is a trusty TH400, manualised and toughened up with billet shafts and ceramic clutch packs thanks to Geelong Automatic Transmissions. This feeds through a 4200rpm converter, back to a strengthened 12-bolt filled with a Truetrac, 3.7s and Moser 31-spline axles.

chev impala interior frontBarnaby purchased the black SS based on the quality of its body and interior, so there was no way he was going to mess with it. Instead he’s added minor upgrades such as Auto Meter gauges, a Billet Specialties tiller and a B&M Pro Rachet shifter to help control the 700hp behemoth

The rest of it is pretty much how it arrived from its Stateside build. Some of the chassis had been boxed, and aftermarket discs had been added up front. “There’s also adjustable trailing arms at the rear, which had been strengthened, and the suspension was already done,” Chris says.

chev impala dashOn all four corners Barnaby has chosen drag-spec 15-inch Weld Vitesse RTs, with the rears wrapped in stomper 28x12.5 M/T Sportsman Pros.

Inside that beautifully restored interior, Dalton Automotive added a few tough niceties to allude to what’s lurking beneath. Steering is thanks to a Billet Specialties jobbie, while a B&M Stealth Pro Rachet takes care of cog-swapping. Auto Meter gauges keep an eye on the vitals.

impala shifter“Barnaby said he wanted over 600hp at the fly, and it’s probably pushing 700hp given that it’s 540rwhp,” Chris says. “He wanted a car that he could drive every day, and I tell you, he drives it nearly every day! Everything was done in-house; the only thing we didn’t do was the machine work on the engine and trans. It’s a beautiful car and a good overall package. Wherever it goes everyone looks at it, because there’s not a lot of loud, big two-door American cars around.”

chev impala interior rearAs for Barnaby, he’s certainly learnt a few things along the way. “This build taught me a lot about getting that sort of horsepower and the quality required to do it,” he says. “I ended up with the most powerful car I’ve ever owned. Chris delivered on my request for a driveable, big-horsepower car to cruise after work, and when I hit the throttle, it’ll go. Hitting the pedal is pretty wild!”

chev impala dashBARNABY LESTER
1966 CHEVROLET IMPALA SS
Colour: Gloss black

POWER
Donk: 500ci Chev
Induction: Holley Ultra 950HP
Heads: Dart Pro 1
Compression ratio: 10.9:1
Cam: Comp Cam solid-roller
Pistons: Mahle dome-top
Crank: Eagle 4340
Harmonic balancer: Pro Race
Ignition: MSD Digital 6AL-2
Fuel: PULP
Fuel pump: Holley Black
Cooling: PWR custom radiator, 16in thermo
Exhaust: Hooker Competition headers; twin 3in system

SHIFT
Transmission: TH400, fully manualised, billet shafts, ceramic clutch packs
Converter: 4200rpm
Diff: 12-bolt, Truetrac, 3.7:1 gears, 31-spline Moser axles

ROLLing stock
Rims: Weld Vitesse RT; 15x6 (f), 15x8 (r)
Rubber: Sumitomo LST (f), 28x12.5 M/T Sportsman Pro (r)

INTERIOR
Wheel: Billet Specialties
Gauges: Auto Meter
Shifter: B&M Stealth Pro Rachet

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