After tiring of his track-only 10-second LS VK Commodore, Dale Bickham went through hell to build this 8000rpm six-litre VC that makes 2hp per cube
This article on Dale’s VC Commodore was originally published in issue no.5 of Street Machine’s LSX Tuner magazine
WE SEE plenty of LS engines making thousands of horsepower, but there is something to be said about taking a good engine base and refining it to the point of art. Dale Bickham certainly did that with his naturally aspirated, six-litre Firethorn Red VC SL, which makes 720hp on pump fuel at a dizzying 8000rpm, all with the stock block, crank and head castings!
“I bought it as a roller from my good mate Todd Foley,” Dale explains. “I had a 10-flat VK drag car with a basic sixlitre that we put a carburettor and dizzy on, and it was a lot of fun, but I wanted a genuine nine-second car in full street trim, as I got sick of towing the gutted VK to the track. The VC was in really good condition, so I sold the VK as a roller and decided to do a few upgrades to the L98, as the VK was much lighter than the fullstreet VC would be.”
That work soon escalated into a nine-month rebuild, with a goal of achieving 2hp per cubic inch – roughly 720hp – from an aspirated 364ci L98 while using the factory aluminium block, stock crank and head castings. Unfortunately, the first trip to the dyno ended in disaster thanks to dud piston-to-valve clearance, so the Gen IV was stripped and sent to Brenton Marusic at Marusic Inductions for a complete do-over.
It looks like Dale just stuffed a killer motor in a stock Firethorn Red VC SL/E, but the truth is much more detailed, with many of those period accessories added later. “I wanted to keep the VC looking as factory as possible, although I didn’t want a ‘perfect’ show car, just something clean,” Dale explains. “I enjoy doing little mods that 99 per cent of people don’t notice but the one per cent who do see them say: ‘Wow! That’s cool!’”
“Brenton and I are both very old-school,” Dale says, “and we decided to use a lot of old-style engine-building modifications in this engine, as many people spend big money on aftermarket strokers and big heads. From running my VZ and VK Commodores I knew the L98 is a good engine, so we decided to push the limit of what a six-litre can do.”
The reverse-cowl isn’t to everyone’s taste, but Dale didn’t have much choice with his tower of aspirated power. “The scoop is a necessary evil, unfortunately,” the Melburnian says. “I want to get a GM intake down the track and machine it so it all fits under the stock bonnet I still have, but money is the issue at the moment”
Running E85 allowed the boys to squeeze the comp ratio up to 15:1 from the previous 11.9:1 thanks to heavily customised 4.005in-bore 12cc JE pistons, while the stock crank was knife-edged, and had billet steel girdle and ARP main studs fitted to keep everything true when spinning at 8000rpm. Lunati supplied billet I-beam 6.125in rods, while the bumpstick is a Cam Motion solid-roller measuring 258/267 duration and 112+2 LSA but with an insane 840/804 lift, working on customised Jet Engineering 8.375in pushrods, Morel solid tie-bar lifters, PAC semi-custom dual valve springs, and Jesel Mohawk 1.7-ratio solid-roller rockers. The L98 heads copped dozens of hours of work to get the flow and air speed right, copping 2.165in Ferrea stainless hollow intake valves and same-brand 1.650in solid stainless exhaust valves.
The factory oil system was gone through so it would hang together at 8000rpm, with the oil pump blueprinted and shimmed, the sump enlarged to 7.5 litres and baffled and a GZ Motorsports crank-case vacuum pump fitted. Similarly, the fuel system is a work of art, with a Carter electric pump in the stock tank feeding United E85 into a boot-mounted 20-litre cell, down –10 200-series Teflon lines to a sprint carstyle BLP internal-bypass mechanical pump. This then tips the street alcohol into the Quick Fuel 1000cfm four-barrel carb perched on a ported LS3-style Super Victor intake manifold.
Backing the screaming six-litre is a reverse-pattern, transbrake-equipped Powerglide and FTI 6800 9.5-inch converter, with a custom two-piece tailshaft handing the paint to a VK BTR78 BorgWarner diff, filled with 4.11 gears, mini-spool, 28-spline axles, plus a diff support hat and a custom anti-roll bar by Marshall Speed Shop. Shocks are 90/10s up front and Koni yellow out back, while all the stock bushes were binned in favour of Nolathane items. The lower rear control arms were boxed and adjustable uppers fitted, with VL Turbo brakes used on the front while VK discs remain out back.
With his goal putting him in the nine-second bracket, Dale had to get a ’cage installed, but got Marshall Speed Shop to tuck it tight against the pillars. The transbrake button has been hidden on the steering wheel
One super-cool aspect to Dale’s SL is the custom big ’n’ little SL/E wheels, spanning 15×4 up front and 15×8 in the rear with custom offset and beadlocks. “I’m not an aftermarket wheel kinda guy,” he explains. “Ron at Eastern Wheel Works modified these wheels for me, but he did take a bit of convincing. The rears were made out of four SL/E wheels using offset welds, kind of like a lapjoint, as that was stronger. Because I knew I would run a small tyre I needed beadlocks, so I bought them out of Queensland and had Ron fit them. Then I convinced him to narrow the two front wheels for me, too!
“After two-and-a-quarter years I finally got the car on the road, but it lasted three days before it started making bad noises from the valvetrain,” Dale sighs. “I locked it away for another three months, nearly rage-quitting and selling it, but was motivated by Holden Nats to get it going again.”
A drop box was used to get the B&M Pro Ratchet shifter largely out of sight
Right off the trailer, with two-thirds throttle and more fine-tuning needed on the fuel system, Dale ran a 10.9@126mph, with the VC tracking arrow-straight and leaving the hole like a treat. We wonder if Todd Foley regrets moving the SL on now?
BUILDING THE TOWER OF POWER
Taking a wild engineering challenge from pub talk to an actual build is a step many don’t make once the beer fog lifts and the realisation of how much work is involved hits. Thankfully both Dale and Brenton were deadkeen to crack the 2hp-per-cube mark using a factory L98 block, crank and head castings, but before they fired up a lathe they started on a computer. “We aimed for the holy grail of aspirated motors, which is 2hp per cube, and we knew we were going to need rpm to achieve that,” Dale says.
Dale had Luke Foley tidy up the engine bay, smoothing it out and hiding much of the messy componentry. The VS master cylinder and booster have custom lines to remove unsightly stock bends, while fresh Firethorn Red was laid down over the neat ’bay
“We fed the basic parameters into PipeMax engine-building software, which gave us calculations to spec-out the camshaft, pistons and the like. Brenton and I did heaps of research when building this combo, but there was also a lot of good old-fashioned engine tech like knife-edging the stock crank to reduce the reciprocating mass.
“The pistons are off-the-shelf items with 12cc domes, and then we poured heaps of effort into making them work with the heads Brenton did, as everything was going to be tight. Brenton spent about 60-70 hours on the heads alone. While the Gen IV has great castings off the shelf, you can’t just hog them out. Although they will get great numbers on a bench, that will cause a lot of turbulence, so you need to work on specific areas in the head.
“Cam Motion in the USA did a custom solid-roller, and while it has a huge amount of lift, it is a low-lash cam that actually sounds quite mild at idle. However, once it starts going through the rev range it just keeps singing and that is because the whole combo works together.
“All up the second build took 15 months, on top of the original ninemonth build. We spent so much time looking at every aspect of the engine, from the Jesel rockers to the highmounted distributor.”
Dale and Brenton achieved their magic figure, scoring 720hp on the first session on the engine dyno, but Dale says there is a lot more coming. “The initial dyno runs are just the tip of the iceberg; there was only four inches of vacuum, but I could do 14 inches, plus I had thick run-in oil in the motor and I could also use drumstyle race fuel like Roo16.”
HOLDEN VC COMMODORE SPECS
Type: Holden Gen IV L98
Crank: Factory, modified
Pistons: JE, modified
Rods: Lunati billet I-beam
Intake: Ported LS3 Super Victor, Quick Fuel 1000cfm 4150
Cam: Cam Motion LLSR, 258/267 duration 840/804 lift 112+2 LSA
Fuel pump: BLP alcohol mechanical, Carter Black lift pump
Gearbox: Two-speed Powerglide
Converter: FTI 6800 9.5in
Tailshaft: Modified WH Commodore two-piece
Diff: VK BorgWarner BTR78, 4.11 gears, minispool, 28-spline axles
Springs: Factory, modified 2in (f), Pedders 3in (r)
Shocks: McDonald Brothers 90/10 (f), Koni yellow (r)
Brakes: VL Turbo (f), VK discs (r)
Rims: Custom VC SL/E; 15×4 (f), 15×8 (r)
Rubber: Nankang 165/80 (f), M/T Pro Bracket radial 26×8 (r)