The aFe Silver Bullet throttle body spacer (46-34008) is a 6061-T6 billet aluminum spacer that mounts between the throttle body and intake manifold on the GM 5.3L V8 in Silverado and Sierra 1500 trucks and Tahoe, Suburban, and Yukon SUVs. Its serrated/helix entry is meant to create turbulence just before the air enters the engine, and the manufacturer says the design also reduces the whistle common to plain helix spacers. The spacer lengthens the intake track, which the manufacturer says raises air speed and sharpens throttle response, and it claims dyno-proven gains of up to +8 hp and +12 lb-ft of torque. Those figures come from the manufacturer, so treat them as its claims.
Compared with a cheap generic spacer, this one is machined for a precise fit to the factory bolt pattern, and the manufacturer lists it as 50-state legal under CARB executive order numbers, which matters in emissions-tested states. Owners on user forums are split. Some report firmer low-end pull and quicker throttle response, especially with an aftermarket intake and a tune, while others on stock trucks notice little difference. Shoppers searching for a 5.3 Silverado throttle body spacer or a GM 5.3 throttle response upgrade should confirm model-year coverage by VIN before ordering, because the manufacturer's product page and install sheet list different year ranges.
The manufacturer's install sheet lists Silverado/Sierra 1500 for 2014-2023 with the 5.3L V8, and Suburban/Yukon XL and Tahoe/Yukon for 2015-2023. Its product page gives a wider range, 2014-2026 for the Silverado/Sierra 1500. Confirm your exact year and engine with the manufacturer before ordering.
The manufacturer states that this spacer is 50-state legal and lists CARB Executive Order numbers D-550-11 and D-550-17.
Per the manufacturer's installation instructions, the spacer is installed with a gasket and fastened with four supplied M6 hex-head bolts and washers.
The manufacturer's install sheet walks through a bolt-on process that starts by loosening the two hose clamps and removing both vent hoses from the back of the intake tube, then removing the OE intake tube. Next, remove the four OE throttle body bolts and move the throttle body aside. Set the spacer and gasket between the throttle body and manifold with the "TOP" side facing the throttle body, then fasten the throttle body with the four supplied M6 bolts and washers, torqued to 5 Nm (45 in-lb). Before you finish, confirm the spacer does not interfere with the throttle plate by opening the butterfly valve by hand. If it does, loosen the bolts and adjust the spacer until the valve clears. The sheet does not give a difficulty rating or tool list, so plan on metric sockets and a torque wrench. Note that the manufacturer's stated torque is low, so do not over-tighten.
