While the stock transmission was sent out for the same treatment as the HOSS, Thomson swapped the LS1 for a prototype 454-cid LSX crate engine. Using a 4.185-inch bore and a 4.125-inch stroke, the small-block achieved maximum displacement with a forged, high-compression rotating assembly. Topping off the 11:1 compression short-block is an LS7-style variety of the six-bolt LSX line of heads GMPP plans to unveil, hopefully some time before Christmas. Stock LS7 titanium 2.20 intake and sodium-filled 1.61 exhaust valves are commanded by stock LS7 rockers and a prototype GMPP 236/246 duration cam with 0.630-inch lift and 110LSA. This is the very same combo used in the 454 LSX in Reggie Jackson's '69 Camaro. But unlike Mr. October's motor, this TA was staying EFI all the way. An LS7 intake, fuel rails and 55-lb/hr injectors give precise port injection and great street manners, though the plastic intake impedes top-end flow enough to keep the motor below the 640 horses Jackson's motor made with the Holley carb and GMPP intake.
Little restriction was left on the exhaust side, as Thomson fabricated 2-inch primary headers with 3-inch collectors, a 3-inch off-road Y-pipe, and a custom axle-back exhaust. The stock fuel pump was sufficient for the naturally aspirated motor, as was the factory computer, harness, and sensors with the GMPP LSX block. An MSD 90mm throttle body with a fabricated bracket mounted on the passenger-side cylinder head made retention of the stock cable throttle and computer possible, along with a 24x reluctor wheel on the crank. A custom tune was needed, but the stock ignition coils and accessories made the grade.
The TA, like the SS, is an example of one impressive solution to the power crisis with aftermarket performance in a factory package. Whether your flavor is the warranty-backed 505-horse LS7, or the more snarling 630+hp LSX, GM Performance Parts has you covered. And now that they have shown us how, it's up to you to decide the when and the where.