As the initial dyno tests are concluded our Project Holden V8 comes off the dyno. The stock 5 litre EFI engine is found to be in great mechanical shape making 296 BHP when tested with Pacemaker 1 3/4" primary header size Pacemaker Tri-Y extractors. With the 1 5/8" Pacemaker Tri-Y pipes peak power is a little lower at 282 BHP. The torque curve for both pipes is very similar in shape with a peak of 338 ft.lbs and 336 ft.lbs for the larger pipe and then smaller pipe respectively. The low end torque for both is very, very close with marginally more for the larger pipe but the torque curve dips several times through the run with the larger pipe. This indicates a mismatch in ram tuning terms between this stock engine and the larger pipe set. One could argue that more power and torque for the bigger pipe dictates the use of that pipe...end of story. There's more to the bigger numbers than that when one relates the shape of the torque curve to actual results in the vehicle. A smoother curve will create a stronger rate of acceleration as the G-Forces created by the engine is uninterrupted. Every time a dip the torque occurrs the car will slow very marginally. As the torque climbs higher again the acceleration will recover and actually increase, but the G-Forces lost will need to be made up. That is not easy and the big pipe car will probably struggle to be quicker than the small pipe car in acceleration.