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Holden 1 Tonner build: part 4

By Mark Allen, 16 May 2018 Reviews

The tonner cops a heap of bolt-on parts.

Holden 1 Tonner build: part 4

ONE of the reasons I chose the GQ Patrol chassis to form the basis of this project was because there are so many off-the-shelf products available for a GQ that it makes the mild-to-wild build pretty easy.

Follow Mark Allen's build on Tonner Files

With everything stripped last month, the time for fitting parts together came via a complete Marks 4WD Adaptors kit. I could have saved a few bucks in the interim by making some parts, but given the scope of this project centred around fitting a 6.2-litre V8 into the GQ chassis, having everything engineered was paramount.

Not only was it easy to deal with Marks 4WD Adaptors, it has everything necessary for the engine-to-chassis conversion, as well as a heap of options. Because the parts in the conversion are ‘off-the-shelf’ and ‘engineered’, it makes it much easier and cheaper in the long run to get the finished product passed by the engineer.

An engineer must still certify that an engineered part has been fitted in accordance with their requirements. This can include welding, fasteners and hardware, as well as positioning on the vehicle – it’s a legal minefield that varies from state to state and from engineer to engineer.

I could have gone ‘engineer-shopping’ to pass larger tyres, higher lifts and more radical mods, but I’ll stick to the reputable fella Jason at Total Care 4WD recommends and who I’ve worked with before for my Troopy’s seating and extra (third) door. Playing the engineering game correctly ensures I’ll have no problems with insurance or potential roadside canaries by the boys in blue.

There was a hiccup, though, with the Marks 4WD Adaptor kit for an LS3 and six-speed auto not mating with the linkage setup of the GQ transfer case. This was easily fixed by swapping for a GU transfer case with the relevant linkage positioning.

The adaptor kit is unbelievably comprehensive with respect to options. On Jason’s advice I chose to delete the Holden Maloo twin-thermo-fan cooling system in favour of a mechanical, viscous hub single fan with shroud to cool the engine. While the thermos can do the job on nice, clean bitumen roads, once you start playing in water and mud they tend to cause more problems than viscous hub units.

A fan shroud is a necessity to keep any engine cool regardless of what radiator you use, so I also ticked that box from Marks.

We’re unsure on a radiator type yet, but an initial play with a 100 Series Land Cruiser unit while at Total Care 4WD seemed to be pretty close to being the right dimensions. More fiddling and trialling is needed here, and a lot will depend on the exact fitting of the cabin over the engine and onto the chassis. We’re also looking at 4.8 Nissan and V8 petrol Cruiser radiators, but time will tell.

I also opted to use the Marks 4WD adaptor extractors, which are a tight-hugging kit that brings down the spent gasses inside the Patrol chassis rails in preparation for whatever exhaust system we bolt on.

We’ve bolted enough of the engine adaptor kit onto the 6.2 to allow a dummy fit into the GQ chassis. To say “it fits like a glove” is correct; everything from the engine mounts, the alternator repositioning brackets, reverse drop sump and the custom tight-hugging extractors that flow inside the GQ chassis rails is spot on and well worth the outlay.

Call me soft, but when the option of chucking an air-con into the Tonner was presented, I jumped for it. Initially we planned on using the compressor as per the standard VE Maloo R8’s LS3, but the electronic workings of it didn’t pan out with the mechanical-orientated system we had our eye on, so it was swapped for an earlier model LS1 version.

I thought about sourcing an air-con unit from an old Holden, but a few ‘old-car experts’ suggested it would be a tough job fitting the unit which bulged into the engine bay. Plus, it would be damn hard to find one in good condition, if at all. That, as well as the fact it would most likely be an under-dash unit taking up valuable cabin space, put me off.

A Vintage Air unit, a mob that supplies air-con units into pretty much anything old with wheels, was suggested. My sparky – Steve at Powers Road Auto Electrical Services – also recommended this system as he’d installed exactly the same unit in his street machine.

With just a little ‘shaving’ from one side of my glovebox, he reckoned it’d fit like a glove under the Tonner dash, and the included flexible piping would marry up with the factory dash vents and demister outlets.

My GQ had both of its sway bars removed by one of the previous owners, which is a practise often undertaken to improve suspension flex when off-road; although, on-road handling goes out the window … and it’s illegal.

I could have dug up a cheap set of Patrol sway bars and mated them with sway bar disconnects to return decent on- and off-road ability and stay within the law, but I decided on a set of Superior Superflex swaybars. These bars feature much longer and larger diameter arms, allowing both much-improved off-road flex (via the longer arms) and improved on-road handling (via the heavy-duty materials).

On the strict advice of my engineer I’ll only be installing two-inch-raised coils. We are currently working with Tough Dog to determine the best spring rates for this application, which will be totally different to a standard GQ Patrol.

Given the LS3 engine and driveline is a different weight to the old 4.2-litre petrol six-banger, Simon at Tough Dog is working with Jason at Total Care 4WD to achieve the best setup. I’ll also be fitting a set of foam cell non-adjustable shocks all ’round. It’s nothing overly fancy, but it’ll be a reliable, effective and well-mannered system both on- and off-road.

A set of 33-inch Cooper STT Pros with Dynamic-imitation beadlock steel rims will grace the old Tonner. Again, given the need to keep my engineer happy, I can’t go larger, but I know plenty of people who ‘legally’ run 35s. I’ve not run the chunky STT Pros before so it’ll be interesting to see what noise levels they return on the bitumen. Off-road, I reckon they’ll maul pretty much anything in their way.

Luckily it’s easy finding many new or replica parts for old Holdens via Rare Spares and Resto Country Spares, from whom I’ve picked up a new interior dome light and bonnet cable release with all associated installation parts. Guards, rust replacement parts, full dashes and pretty much all ancillary parts are available for full rebuilds if needed.

4x4 Buyers' Guide: Aftermarket fuel tanks

The petrol GQ Patrol I picked up was also running LPG, which involved the removal of the main rear-mounted 95-litre petrol fuel tank and installing a mid-mounted smaller tank, which, I’m guessing, is 40 to 50 litres. I’ll not be running LPG, so I’ve got the OE fuel tank void to fill. I’ve contacted Long Ranger for a custom-built tank.

While I don’t have the tank yet, Long Ranger reckons it can easily modify its existing aftermarket GQ 147-litre tank and mount a sender unit and fuel pump from my model Dunnydore. At worst, Long Ranger figures I may lose a litre or two in volume, but hey, in the end that’s pretty damn good and it is yet to be fully confirmed.

I’ll attempt to keep the mid-mounted petrol tank and rig-up a fuel transfer pump to move the spare fuel rearwards when needed, giving a total of roughly more than 200 litres.

That should see the 6.2-litre get to the shops and back. This extra weight also makes a difference to the rear coil spring rates, so we’re ultimately holding off choosing springs with Tough Dog until we can confirm all these weight-related details that can affect the suspension system.

The old Tonner rear-view mirrors, while looking the part in the ’70s, are way too small and I spent an age looking for a suitable replacement. My standard rectangular Troopy mirrors are spot on – other than the mounting foot not suiting the Tonner panels – so I wanted something similar.

Low and behold, 60 Series Cruiser mirrors offer a similar size and an (almost) ideal-shaped mounting foot for the smooth lines of the Tonner. Terrain Tamer stock them and they seem to be a pretty solid mirror and mounting system.

Next month, we’ll look at dropping the Maloo seats into the cab, GQ steering column into the dash and the Tonner cabin onto the chassis, along with more discussions with the engineer to ensure a painless final check and registration process. That’ll be interesting.