Family-friendly firepower: blown, big block Impala family hauler

3 February 2024

“When a teenage David Vea dreamed of owning a big block muscle car, he never expected to realize that dream in something the whole family could enjoy”

We’ve all got our dream cars. What would you build, should you find yourself in the position to build the one car that ticked all the boxes for you? For some, it would be a refined version of a dream held since childhood, while others might desire something they had never even realized existed until quite recently. For David Vea, it was more of the former — while he had dreamed of owning a big block–powered car since he was a teenager, chances are he never imagined that, if he ever did, it’d be in a ’65 Impala coupe.

Life forces most of us to leave the carefree days of being a teenager behind, and it was no different for David. He’s owned a few toys of his own, including a V8-powered Holden HQ and Ford Falcon XF, but when you’ve got a family and all the attached responsibilities, sacrifices sometimes have to be made. Those cars came and went, but David never let go of that long-held dream to own a big block some day, no matter how unlikely it seemed.

Then, around three years ago, David realized that if he was ever to do it, that was as good a time as any. He sat down with his wife, Hayley, and had a serious discussion about starting a build, with the long-term goal of owning that big block car he’d always dreamed of. With three kids, they decided to look for something that’d comfortably fit the whole family, and that meant a big car. “And, for my ego, I wanted a loud, angry engine to match the size of the car!” David laughs. “I dreamed of going on cruises with my family and friends, with plenty of room and good times enjoyed by all — and having power to burn!”

David initially looked towards larger B-body Mopars, such as a Plymouth GTX or similar. However, having always had a soft spot for ’65–’66 Impala coupes, his decision-making path slowly steered him towards a Bowtie-badged big block.

“Seeing Bruce’s ’65 Impala, which was featured in your magazine, [the cover of NZV8 Issue No. 36] made me appreciate these models and how they can be transformed into a muscle machine, instead of the traditional cruiser,” David explains of his decision to look at full-size Chevs.

While stacking the pennies, David stumbled across a tidy, and completely factory, ’65 Impala coupe on Trade Me. With a 327ci small block and two-speed Powerglide transmission, it was a world away from the big block beast David wanted, but he knew it would make a solid base for the mega-power build.

“I found myself drawn to this car,” David told us, “as it ticked nearly all the boxes — the colour, the front bench seat, the model. I decided I’d better discuss the big block idea with a friend, Rod Pickerell from Speedwell Tune & Service Centre, Hamilton, and he said it was a feasible concept, but suggested that I talk to a friend of his.”

That friend was Craig Hammond, who has done the very transplant in question a number of times, and knew his way around an Impala blindfolded.

“After consulting Craig and putting together a budget — which ended up doubling! — I decided it was a viable option,” David says. “Over the next couple of days, I kept looking at the Impala on Trade Me. Then I decided, That’s it! Let’s do this!”

Without warning, or any real planning, David went and looked at the Impala after work, and ended up coming home in a new car. On the way home, he rang Craig and told him that he’d purchased the car, and was ready to get the ball rolling.

The original plan was to stick a naturally aspirated 505ci big block in there and be done with it. However, when the engine was sent away to have the stroker bottom end blueprinted and installed, the possibility of wanting more power in the future led David to enquire about going blown.

Craig said that this was totally doable, and that David had got in just in time — the bottom-end recipe was slightly changed, with displacement dropped slightly to 496ci. This is thanks to the 4.250-inch stroke of the Eagle 4340 steel crankshaft, with Eagle rods and forged CP pistons hanging off it. A Comp Cams solid roller camshaft with a boost-friendly profile controls the intake and exhaust events, and is paired with Comp Cams solid roller lifters, with some super-tough hardware bolted to the AFR Magnum heads. Huge REV valves, Comp Cams roller rockers, retainers, and valve springs all add up to a hardy engine assembly, up to the task of handling an unfeasible amount of power.

The reason for all this is clear — bolted to the top of the motor is a huge Littlefield 8–71 blower, sucking more than its fair share of fossil fuels through a pair of boost referenced Quick Fuel 850cfm carburettors. In cold, hard numbers, the end result of this is a staggering 920hp — more than enough in anyone’s books.

“I remember when the engine was dynoed at Marsh Motorsport,” David recalls. “My wife and I were in Sydney, and Craig rang me at 6am over there. I was eagerly awaiting his call, and when he gave me the good news, it put a smile on my face from ear to ear.”
Having such force under the bonnet meant the rest of the driveline would need to be beefed up to suit. Chuck Mann from Rotorua V8 Performance was tasked with building a transmission up to the task, and the manual valve-bodied TH400 he fronted up with is a tough piece of gear, just as the GM 12-bolt diff out back is. With an Eaton Trutrac centre, Motive Gear 3.48:1 gear set, and Moser axles, the only thing that breaks when David puts his foot down is traction.

In stark contrast to the monstrous engine and drivetrain combo, the remainder of the car is a lesson in restraint. Global West tubular front A-arms and Global West coil springs have the big Impala sitting right over its big, dished 20×8.5-inch and 20×9.5-inch US Mags wheels. David would like the front end to sit a little lower, but that would mean the huge 2¼-inch primary Hedman headers would scrape the ground a little too much for comfort. While this wouldn’t be a problem for a show pony, David drives the car as much as he can, and we all know the state of some of this country’s best roads.

The Impala was finally ready just in time for the 2015 Mothers Chrome Expression Session, and David made the milestone drive with three mates, for a great weekend that included plenty of cruising and even taking out the top place in the show ’n’ shine. Cruises like that will be a common sight for this car, as David’s always wanted his friends and family to enjoy it, too. He’s a great bloke, always happy to have a chat if you happen to see him at a cruise or event — just don’t ask him about his fuel economy!

Specs

Vehicle: 1965 Chev Impala coupe
Engine: 496ci big-block Chev, 10.2-inch deck height truck block, Eagle 4340 crankshaft, 4.250-inch stroke, Eagle 6.8-inch H-beam rods, ARP L19 rod bolts, custom CP pistons, ATI Super Damper harmonic balancer, Moroso oil pan, Moroso oil pump, Moroso oil pick up, Comp Cams solid roller camshaft, Comp Cams Elite Race bushed solid roller lifters, Trend 7/16-inch pushrods, AFR 305cc Magnum heads, REV stainless steel 2.22-inch intake valves, REV Inconel 1.88-inch exhaust valves, Comp Cams valve springs, Comp Cams titanium retainers, Comp Cams Pro Magnum roller rockers, Littlefield supercharger manifold, Littlefield Competition 8–71 supercharger, twin Quick Fuel 850cfm boost-referenced carburettors, -10 fuel lines, MagnaFuel ProTuner 750 Series fuel pump, MagnaFuel fuel pressure regulator, MSD 7531 programmable CDI ignition, MSD crank trigger, MSD Pro Billet distributor, MSD HVC2 coil, Moroso leads, Hedman Husler 2¼-inch primary headers, four-inch slip-on collectors, 3½-inch exhaust system, Dynatech mufflers, RPC radiator, Davies Craig thermo fan, custom fan shroud
Drivetrain: GM TH400, manual valve body, Auto Trans 3000rpm billet stall converter, TCI SFI flexplate, GM 12-bolt diff, Moser axles, Eaton Truetrac centre, Motive Gear crown wheel and pinion, 3.48:1 ratio, Strange Engineering billet yoke, custom 3½-inch driveshaft
Suspension: Global West tubular control arms, GM four-link rear, KYB shocks, Global West coil springs, 1⅛-inch front sway bar, Prothane bushes
Brakes: Wilwood dual master cylinder, Wilwood Dynalite front calipers, GM front rotors, Wilwood Dynalite rear calipers, Wilwood rear rotors
Wheels/Tyres: US Mags standard wheels, 20×8.5-inch and 20×9.5-inch
Interior: Auto Meter Pro Comp gauges, B&M Pro Ratchet shifter, factory bench seat, factory steering wheel
Performance: 920hp at 10psi boost (Avgas)