LS-based engines factory installed into so many late-model Pontiacs are a hot rodder’s dream. The entire Gen III/Gen IV engine family is a straightforward yet effective design that’s been embraced by the aftermarket on many levels. A wide array of components intended to accentuate or significantly boost their already-impressive performance levels is readily available from many sources.
Like traditional Pontiac V-8s, the architecture among the entire Gen III/Gen IV family allows for easy component interchange. We contacted three companies on the forefront of late-model performance and asked each to share the intimate details of the LS-based engine package that’s most popular with Pontiac hobbyists. Installation into any Fourth-Gen Firebird, GTO, Grand Prix GXP, or G8 is relatively simple, requiring minimal modifications.
Follow along as we take an in-depth look at some of the engine packages that can be found powering many Pontiacs today. You might find one that fits your performance expectations, and budget too!
Mast Motorsports 416ci LS3
Mast Motorsports has been building Gen-IV engine packages for several years and it can be considered a one-stop shop for late-model GM performance. In addition to a complete line of aftermarket powertrain components such as cylinder heads and camshafts, Mast Motorsports also offers complete LS engines, and its LS3-based, 416-inch offering is very popular with Pontiac owners. Generating more than 600 hp, it offers consistent and reliable performance and installs easily into most any chassis.
Projected Output
Horsepower: 639 at 6,500 rpm
Torque: 554 lb-ft at 5,400 rpm
Block: Original GM aluminum LS3
Year: ’08 to current
Bore in Inches: 4.070-in
Cubic Inches Before/After Build: 376ci bored and stroked to 416ci
Bottom End
Pistons: Mahle flat-top with 4cc valve relief volume
Rings: Mahle
Rods: Callies Compstar, forged 4340 steel, 6.125-in length, 2.100-inch rod-journal diameter
Compression Ratio: 11.2:1
Crankshaft: Callies Compstar, forged 4340 steel, 4-in stroke
Mods: Balanced
Oiling System
Oil Pump: Melling, high-volume
Windage Tray: Mast Motorsports stroker
Oil Pan: Mast Motorsports LS conversion
Induction System
Air Filter: Mast Motorsports with IAT
Intake Manifold: Stock GM LS3 or FAST
Mass Air or Speed Density: Speed density
Throttle Body: GM LS3 90mm
Fuel Injectors: GM LS3
Fuel Management System: Mast Motorsports M120
Tuner: Mast Motorsports, Nacogdoches, Texas
Heads
Brand or Casting Number: Mast Black Label CNC for medium bore
Mods: CNC-machined, Mast proprietary design, 0.075 deck surface
Airflow Numbers: 361/247 cfm at 0.600 lift at 28-in of pressure
Valves: Mast Motorsports 2.165/1.6-in
Valvesprings: PAC dual springs
Pushrods: Mast Motorsports 8.05-in
Head Built By: Mast Motorsports
Camshaft
Brand: Mast Motorsport LS3 SS hydraulic roller
Duration at 0.050: 230/237-deg
Lift with Specified Rocker Arms: 0.608/0.615-in
Intake Centerline: 116-deg
Lobe Sep. Angle: 112-deg
Rocker Arms: Stock GM LS3, 1.7:1 ratio
Ignition
Type: GM Gen IV LS3
Coil(s): Stock GM
Wires: Mast Motorsports Black Label
Spark Plugs: NGK
Exhaust
Headers: Not included
Recommended: Muscle Rods tubular
Primary Size: 1.875-in
Collector Size: 3.00-in
Price and Part Number
$14,995 with control package PN 111-223 (ECM and harness)
Fits Which Chassis
Any LS-based Pontiac chassis
Options
A centrifugal Magnuson TVS 2300 ($7,000) adds 100-200 peak horsepower but offers increased power throughout rev range, and more than 500 lb-ft of torque just off idle.