LSX376 Crate Motor
This GM Performance Parts crate engine, along with the higher-output LSX454, debuted at the '08 SEMA show. Billed as a budget assembly, the LSX376 is based on an iron standard-deck (9.26 inches) LSX block and LS3 cylinder heads (PN 12615879) with rectangular-shaped intake ports that flow more than the cathedral port heads, but less than the wider-port LS7 heads. These heads are for any LS-family engine with a 4.00-inch (or larger) bore size. They maintain a max valve lift of 0.570-inch, 68cc combustion chambers, 2.165-inch hollow-stem intake valves, and 1.59-inch solid-stem exhaust valves. As cast, the intakes will flow at least 316 cfm at 0.600-inch lift.
GMPP holds down overall cost by using a nodular crank and powdered rods, but includes a premium forged piston. Note that the specific crate rocker covers do not have provisions for mounting the ignition coils, hence an aftermarket arrangement is required. Also, this engine does not come with an oil pan, windage tray, or pumping system. You must choose the oiling system that suits your application from the GMPP catalog. With the factory-issue EFI LS3 intake instead of a carburetor, this engine produces 485 hp at 5,750 rpm, and 475 lb-ft of torque at 4,500 rpm.
This package is the introductory stage to the new LSX series, and it begs the obvious question: Who needs an iron-block version of the extant LS3 crate engine? View the LSX376 as a foundation for much more power and torque, but at, say, 600 rats. How much more do you really need? That's right, you don't but if you did give it more oats, you'd sleep well and have a clear conscience about loading up an iron block with them.
And to that end: A chat with GMPP's Dr. Jamie Meyer confirmed that GMPP will soon be introducing short-block and long-block versions of the LSX376 equipped with a forged 9.0:1 piston meant specifically for use with a forced air induction system. Boost-friendly camshafts are also in development, and will be available individually, or as part of a low-compression short-block. Blower and turbo testing of various aftermarket kits is underway at this very moment. Whatever system(s) deemed proper will likely be licensed and sold by GMPP. This proactive move is a positive indication that the boys in Flint will be doing a lot more testing before the latest products are released.-Ro McGonegal
| BY THE NUMBERS |
| LSX376 |
| Part number: | 19171049 |
| Engine type: | LSX Series Gen IV small-block V-8 |
| Displacement (ci in/L): | 376ci/6.2L |
| Bore x stroke (in.): | 4.06 x 3.62 |
| Block (PN 19166454): | LSX cast iron with six-bolt, cross-bolted main caps |
| Crankshaft: | nodular iron |
| Connecting rods: | powdered metal |
| Pistons: | forged aluminum |
| Camshaft type: | hydraulic roller |
| Valve lift (in.): | .551 intake/.522 exhaust |
| Duration (degrees at 0.050 in.): | 204 intake/211 exhaust |
| Cylinder heads (PN 12598594): | LS3 rectangular port; as cast with 68cc chambers |
| Compression ratio: | 10.7:1 |
| Rocker arms: | investment cast, roller trunnion |
| Rocker arm ratio: | 1.7:1 |
| Recommended fuel: | 92 octane |
| Reluctor wheel: | 58x |
| Balanced: | internal |