Truck intake vs LS6 intake

Both are cathedral-port, long-runner factory intakes, and both are good. Richard Holdener's testing found the factory early truck, LS2, LS6 and especially the TrailBlazer SS intakes all work well; only the original 1997–2000 LS1 intake is a weak spot. The practical differences:

• Truck intake: the most common junkyard intake. It's taller, so hood clearance is the usual issue in car swaps.
• LS6 intake: lower-profile car intake, standard on all 2001+ LS1/LS6 engines; the common upgrade on older LS1s.

Upgrade example: on a cammed 5.3 (L33), swapping the stock truck intake and 78 mm throttle body for a FAST LSXR and 102 mm throttle body went from 456.5 hp to 480.7 hp, with nearly all of the gain above 5,000 rpm (OnAllCylinders / Holdener).