Bolting It Together
With the key elements of our new parts combination in mind, we brought our 502 big-block and the requisite parts to Outlaw Racing for machining and assembly. With the original GM 502 combination, flat-top pistons were employed with the small 110cc chamber oval-port heads for a compression ratio of 9.6:1. With our parts combination aimed at higher rpm and a much more aggressive camshaft, some changes were due for the bottom end. Upgraded pistons was high on that list, since with the larger chambers of the Trick Flow heads, the compression ratio would be far too low with the existing pistons. Since our intent was a fully blueprinted rebuild with a .030-inch overbore, we selected the 17cc-domed SRP pistons, which yield a very pump-gas friendly compression ratio of 10.1:1 with our cylinder heads.
As a further nod to durability, the rods were upgraded to Eagle's bulletproof 4340 forged H-beams in place of the original I-beams. Mitchell bored and honed the block to a 4.500-inch bore size, index-surfaced the block to achieve a zero deck height, balanced the rotating assembly, and then proceeded to final assembly. Far from a complex build, Mitchell relates that the engine was very straightforward to assemble. "We really didn't have any problems with anything," he says. "It actually went together very smoothly. We built it in stages, and put the short-block together first, and then later put the top-end on it. It was pretty pain-free really."
Many of the parts from the original 502 were reused, while new Clevite bearings, Fel-Pro gaskets, and Sealed Power rings made up the basic rebuild components. The camshaft was installed using a COMP timing set, and degreed to a 101-degree intake centerline angle. The cam was entombed by a COMP two-piece aluminum timing cover, which separates the cam cover from the function of sealing the oil pan rail.
As the crew at Outlaw Racing dropped in the new MSD Pro Billet distributor and screwed in a fresh set of Champion C61 spark plugs to complete the final details on our now 509ci big-bore Chevy, we were chomping at the bit to see what this thing would do. It wasn't long before we trucked it to Westech Performance Group and bolted to their SuperFlow 902 dyno for the numbers. With the tight-centered solid-roller cam operating the valves, the dyno cell resonated with the bark of power. The engine moderately loped at the steady idle following the dyno's automated engine break-in cycle. Dyno operator Steve Brule worked through the normal checks and adjustments required of any new engine assembly. Then we drained the crankcase of the Royal Purple 10w30 break-in oil for a fresh load of their standard 10w30 synthetic and installed a new Fram TG-30 filter.
When the hammer was dropped, the engine did not disappoint. The tight-centered solid-roller cam worked in concert with the Trick Flow heads to really feed the beast, tuning in to produce explosive torque as the tach began to swing upward. A peak torque of 651 lb-ft at 5,100 rpm was recorded; that's a very stout number for 509 cubes at just over 10:1 compression and swilling pump gas. It was obvious from the torque reading that we had a very happy combination with this engine, with a gain of 96 lb-ft over the original fuel-injected 502 engine combination. With all that torque came no shortage of horsepower, as the engine pulled eagerly to 6,500 rpm, posting a peak of 717 hp at 6,300 rpm. The reconfigured engine was churning out well over a 200hp gain. With our 509 Chevy's crushing midrange torque and the substantial punch delivered at the top, this engine earned its "Pile Driver" name.
Timing the cam is a step that should never be shortcut when assembling a high performance
For a durable finish, the short-block was given a coating of Dupi-Color engine enamel in C
A Melling oil pump works with the stock pick-up, windage tray, and pan to provide for lubr