Turbo HR Special

Ever heard the saying “Old Holdens Never Die”? Well, not only do they live on, some grow a turbocharger and programmable engine management!

Paul Barone’s Holden HR Special wagon is one of the hottest ol’ Holdens that still manages to remain true to its heritage – sure, there’s plenty of modern technology under the bonnet but the body and interior suitably reflect the era. It’s not likely a set of polished 20 inch wheels and a towering rear wing would suit...

Paul picked up this HR wagon from a friend of the family – it was the ideal platform with just 100,000 miles on the odometer, neat presentation and a relatively minor amount of rust. Initially, Paul used the car as a hack but on one fateful day he stumbled across a turbo kit to suit the Holden straight-six. Interestingly, the kit carried genuine GMH stamps and was perhaps intended for use on the limited production turbocharged Toranas of the late ‘70s. But, amazingly, this particular turbo kit had remained unopened for around 30 years...

The kit comprised a single side-draught SU carburettor, Garrett turbocharger, exhaust manifold and a spacer plate to reduce the compression ratio. Recognising the limits of the increasingly tired 186ci (3050cc) engine, Paul elected to rebuild ‘er with an O-ringed block, forged pistons, heavy-duty rods, a 12-port Yella Terra head with larger valves and a mild camshaft. A five-core radiator was also fitted for peace of mind. With the turbo kit attached, the engine made good torque but all attempts to run a decent amount of boost were unsuccessful. There simply wasn’t enough tuning flexibility in the draw-through turbo set-up.

At this point, Paul approached Silverwater Automotive Services (SAS) and decision was made to update the entire induction and fuelling system. The carby arrangement was ditched to make way for a VK Commodore EFI intake manifold combined with an Autronic management system. The Autronic controls a set of six Bosch injectors and a high-pressure fuel system (complete with surge tank) is installed. The ignition is a single coil arrangement teamed with a modified distributor.

With more boost on the agenda, a new T3/T4 turbo was mounted on a custom tubular exhaust manifold and a PWR water-to-air intercooler was included. An atmospherically venting blow-off valve is installed between the ‘cooler and throttle body. The turbocharger now draws air through an under-bonnet pod filter and a 3 inch mandrel bent exhaust lets the boosted six blow out its spent gases.

Backing the turbo engine is a high rpm Dominator stall converter teamed with a tricked Powerglide transmission. A heavy-duty tailshaft sends torque to a Holden VL Turbo diff which has been shortened to suit the HR. And is it tubbed, you ask? Amazingly not. Those 265mm rear tyres are as big as will fit without needing panel mods.

After experimenting with the VL Turbo rear disc brakes and experiencing bias problems, Paul installed a pair of Holden HQ rear drums (which are substantially bigger than standard) along with a Torana disc front-end. The suspension has been renewed with Pedders lowered springs and dampers. The steering is the standard HR arrangement.

While all this was going on, Paul gave the body and interior the revamp that it deserved.

The panels were striped to bare metal, all rust was cut out and a new coat of the standard paint was applied. The white-on-green scheme is how this particular vehicle left the factory. The bumpers are brand-spankers new and much of the other external trim has been re-chromed – but there’s one pesky part left to go... Despite his exhaustive searching, Paul has had no luck finding a tailgate window surround in mint condition. Damn! Wheels are suitably styled 15 inch Convo Pros.

Given the relatively low number of miles travelled, Paul hasn’t had to perform a major interior rejuvenation. Instead, all he’s had to do is replace the dash pad, roof lining and the base of the front bench seat. The door trims and everything else remains in unbelievably good condition – there’s even the original radio (which is fully functional)! Paul has also replaced the factory gauges with new AutoMeter items displaying speed, rpm, boost pressure, coolant temperature, fuel level, oil and fuel pressure. The gauges are well suited to the late ‘60s styling of the HR.

Paul says he’s now pretty happy with the way the HR presents and runs. Unfortunately, there is some rust beginning to re-emerge and that will need to be taken care of before it takes hold. Oh, and that missing tailgate trim is enough to drive a bloke insane – if you know the whereabouts of this part, please contact Paul via michael@autospeed.com

It’d be nice to finally add that finishing touch!

Contact:

SAS
Silverwater Automotive Services
02 9748 1300
info@silverwaterauto.com.au
www.dynotuning.com.au

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