I met the team at Henson & Murray Engine Rebuilders in 2002 when a few mates and I started building the HQ Holden race car. Brian & Scott are a very friendly and professional team and looked after me. They took the box of Big Block Chev parts I had amassed and they machined a strong 461ci engine out of them. Being on a small budget, the main aim was reliability and that is what we got. Bigger parts and more power came over the next few years.
Each time I could afford to change the engine combo Scott & Brian were ready with helpful advice and suggestions to make the most power from my dollars. Increasing the bore to make 475ci and upping the compression brought quicker times on the drag strip and the craving for even quicker times and more power.
A quarter inch stroker crank pushed us to 505ci and this deserved a roller cam. Again Scott and Brian were there to support and help with the finer details so that what was put together stayed together and made the power that was wanted.
Then it came time to take weight out of the car and have it sit lower. The rear was mini-tubbed and the heavy glass screens were replaced with polycarb. The car looked better, handled better and ran quicker.
Curiosity about the true power output had me take it to a chassis dyno for testing and a bit of tuning. I brought the results back to Scott and Brian. The loose torque convertor gave rather large and mis-leading readings so they suggested I pull the engine out and they would take it to Marsh Motorsport in Auckland to get accurate and true readings.
When the engine came back they had the dyno print-out and 40hp more than when it went up. That sort of HP is impossible to find at the track. The final tune was set as a “general” tune so I wouldn’t have to mess about at the different tracks. That tune worked brilliantly. A looser torque convertor was recommended and that was purchased to match the engine combo.
It was mentioned in passing at the dyno that the car had been seen and the 505bbc heard at the track. It had a distinctive sound in the burnout and launch and that I was treating the engine the way it should be treated... (Without being reckless) This engine sang. It did everything I asked and was there ready for the next race every time without fail.
The 2009/2010 season was very successful. Running personal bests in ET and MPH. Racing the NZDRA National series saw us at Meremere , Taupo, Masterton, Christchurch and back to Meremere for the 42nd NZ Nationals and NZDRA Series point’s final. Winning the NZ Nationals Super Gas class gave me enough points to win the NZDRA Series in Super Gas. On the way posting a PB 9.88 sec ET and several low 9.9 sec passes while having to slow to avoid breaking out. Masterton gave me 138mph.
A set of aluminium cylinder heads were purchased for the 505 and Brian and Scott took the time to get them into shape and make them work. The improvements from the heads gave me consistent low times and much improved performance at Taupo… (Being at a much higher altitude than the other tracks).
Next it was time to make these heads really work. The bore of the 505 was causing shrouding of the valves. The next move was to purchase a Dart block where the bore could be really opened up. When funds became available a new dart block was purchased and taken to Scott and Brian and the team at Henson & Murray for massaging and machining. The crank and cam were taken from the old 505, and the block bored 60 thou giving a 555ci combo.
This is currently waiting for the new front end to be finished in the race car and new headers built so it can breathe properly. Then taken back to the engine dyno for break-in and tune.
Over the years, whether it has been the race car engine or my street car big block, the service, expertise and professionalism from the Henson & Murray workshop has been first class. Nothing goes out unless it is right. Scott and Brian take the time to explain what wrong, what’s required to be done and what are the best parts needed to get it right. This proven service is reflected in the wide variety of engines that come through the workshop to be returned to as new or better condition.
I would like to thank the Henson & Murray team for their dedicated support over the years and for the reliability they build into the engine to get me from the start line to the finish line every time.
Masterton Dec 2016
Update August 2017.
After a few years being spent modifying the car and a new engine built as well as strengthening the TH400 trans (Chuck Mann) the car completed its first full season (2016-17) very successfully. Scott and Brian have assembled a very strong 555ci Big Block Chev for the HQ using the crank, cam and heads from the 505ci BBC. The aluminium RHS heads and Dart Intake were sent to Marsh Motorsport in Auckland for treatment. The 1050 Holley Dominator was modified by AED Carbs and now flows 1200cfm.
The car itself received a custom strut front end, to accommodate larger headers and lose some weight. This was easier said than done but was very successful.
The car with driver weighs 3300lb/1500kg and runs 9.18 @ 147.29mph this calculates to approx 830hp. My target when building the engine was 820hp with reliability. The engine has yet to be dyno’d and a final tune put into it but I am very happy with the result so far.
Early December 2016 saw the car at Masterton although the Sunday finals was rained off, qualifying on the Saturday enabled us to iron out a few gremlins but still run a PB of 9.58 @ 139mph.
The end of December we raced at Taupo. Losing in the semi-finals on a red light but still ran a 9.6 @ 141mph. A PB for Taupo track bettering the previous 10.0 @ 134mph. (Dec 2011)
February 2017 we raced at Meremere. An off the trailer 9.55 @ 145mph looked promising. With a change of fuel to VP C12 the next run was a 9.36 @ 145.6mph. We ran several more 9.3s at Meremere over the next few meetings and 146+mph.
March 2017 was the NZDRA Nationals at Masterton. After qualifying well on the Saturday and the car running strong we put down a PB of 9.18 @ 147.29 mph on a very good track in fantastic weather and went all seven rounds to win the Super Sedan title at the 49th NZDRA NZ Nationals.
Thanks for your support.
Again a huge thanks to Brian & Scott and the team at Henson & Murray Engine Rebuilders for the strong reliable 555ci Chevy and their continuing support.
Thanks to grumblo.com for the above video clips.