It's a little intimidating at first. You know it's just another engine. It's got all the same stuff a traditional small-block has, like pistons, crank, rods, a cam, and lifters-but this one has been masked in an unfamiliar dress. This one is skinned in aluminum and lacks the traditional painted iron block and deep-sumped oil pan. Plus it sports metric hardware instead of the American units we are accustomed to. Don't kid yourself though. This all-aluminum mill means business, and it has become one of GM's tried-and-true thoroughbreds of the new millennium.
For this month's test, rather than piecing something together from scratch, we opted for a complete LS2 short-block from Turn Key Engine Supply out of Oceanside, California. Inside the aluminum fortress rests a Lunati LS1 Pro Series stroker kit assembly featuring a 4340 forged crankshaft with a 4.00-inch stroke, 4340E billet rods, and forged JE Pistons with valve reliefs.
Once we began to unzip its skin to reach the insides, it was clear GM knew what it was doing from the factory. Cam swaps from stock to aftermarket can be achieved without dropping the oil pan. Case in point, we had two solid-rollers to try out. The first was right out of Comp's catalog (PN54-500-11), which specs out at 235/240 intake/exhaust and 0.646/0.641 intake/exhaust duration at 0.050 inch with 113 lobe separation, while our second, more aggressive cam (PN 54-501-11) features a 243/248 intake/exhaust and 0.653/0.648 intake/exhaust duration at 0.050 with 113 lobe separation. Both were paired with a set of their linked solid-roller lifters. Our cylinder heads of choice? We couldn't pass up a chance to test Trick Flow's newest fully CNC'd units. They feature 340 cfm of flow at 0.600-inch lift. Additionally, the build wouldn't be complete without throwing a little juice and fuel down the mouth of an Edelbrock Victor Jr. manifold via a Holley 1,000-cfm HP carburetor and a Zex perimeter plate.
How well did our 402-inch short-block fare with the new cams, lifters, and tremendous flow from the cylinder heads? Read on. We think you'll be impressed by the results.
Quick Notes
What we did
Tested Trick Flow's latest 235cc cylinder heads, two Comp Cams solid rollers, and a Zex Perimeter plate
Bottom Line
600 hp on the motor and nearly 800 hp on nitrous
Since we were starting with...
Since we were starting with Turn Key's 402-inch short-block, the only components removed to gain access to the cam were the balancer and front timing cover. We used an 8mm socket to remove the cover bolts, and once it was out we found TDC and pulled the cam.
To find TDC, Ernie Mena lined...
To find TDC, Ernie Mena lined up the timing dots on the upper and lower gears. Once they were matched up, we could remove the timing gear bolts. The cool part about this: The oil pump doesn't need to be removed and neither does the lower crank gear.
With the timing gear off and...
With the timing gear off and the chain off to the side, we removed the Torrington bearing and cam plate.
We wanted to take full advantage...
We wanted to take full advantage of the LS2's high revving potential with the new solid-roller camshaft, and that meant the hydraulic lifters had to take a hike. In order to access the lifters, we first removed the factory lifter tray and simply pulled them out.
With the lifters out, we could...
With the lifters out, we could then remove the old camshaft, all the while being careful not to nick the cam bearings. When installing the new camshaft, be sure to place liberal amounts of assembly lube on the cam lobes before sliding it in.
For head gaskets we went with...
For head gaskets we went with Fel-Pro MLS (PN 1161R and PN 1161L), which have a 4.100 bore and a compressed thickness of 0.053 inch. The multilayer design can withstand higher combustion chamber pressures, which we were anticipating with the added use of nitrous. To prevent any confusion over which way the head gaskets should lie, each gasket is labeled either "L" for the driver side or "R" for the passenger side.