Mercruiser 496MAG / 496MAG HO Marine Performance Parts

Running an inboard 496cid / 8.1L engine in your yacht or powerboat? Raylar’s marine performance packages are bolt-on replacement parts for any Mercruiser 496 MAG / 496 MAG HO, Volvo Penta 8.1Gi / 8.1GXi, Crusader Captain’s Choice 8.1 MPI / 8.1 HO MPI, Levitator 496cid or Marine Power 8.1. We’ve developed our marine performance kits to raise the level of performance, reliability and efficiency available from these engines.

Our products are direct bolt-on replacements for any of these marine applications.

  • Mercury Mercruiser
  • 8.1L / 496 MAG
  • 8.1L / 496 MAG H.O.
  • 8.1L Horizon
  • Volvo
  • Penta 8.1 Gi
  • Penta 8.1 GXi
  • Crusader
  • Captain's Choice 8.1 MPI
  • Captain's Choice 8.1 H.O. MPI
  • Other Makes
  • Levitator 8.1L / 496cid
  • Marine Power 8.1 MPI
  • Vortec 8.1L / 496cid

Marine Performance Parts

mercury marine mercruiser 496 performance parts
525HO / 496cid Stage 1 - $6989

Our stage 1 marine performance package bumps the 496 / 8.1L to 540 horsepower & 600 ft-lbs of torque.

  • BigPower Aluminum Cylinder Heads
  • BP-203 Street / Strip Camshaft
  • CoolGap EFI Intake Manifold
  • 1.7 Ratio SS Roller Rockers & AFN nuts
  • ARP Re-torqueable High Strength Head Bolt Kit
  • Cometic MLS Head Gasket Set
mercury marine mercruiser 496 performance parts
600HO / 496cid Stage 2 - $8699

Our stage 2 marine performance package bumps the 496 / 8.1L to 605 horsepower & 635 ft-lbs of torque.

  • BigPower Aluminum Cylinder Heads
  • BP-206 Max Effort High-Lift Camshaft
  • CoolGap EFI Intake Manifold
  • Billet Throttle Body
  • 1.7 Ratio SS Roller Rockers & AFN nuts
  • BigPower Forged Flycut Pistons, Rings & Wristpins
  • BigPower Forged H-Beam Connecting Rods
  • ARP Re-torqueable High Strength Head Bolt Kit
  • Cometic MLS Head Gasket Set

Raylar 511 CID Stroker Performance Kits

Want even more power? Our 4.5" stroke crankshaft, forged h-beam connecting rods and forged pistons replace your exisiting rotating assembly adding cubic inches and more power. Direct replacement parts for your stock rotating assembly.

raylar 8.1l 496 stroker kit
Raylar 511cid Stroker Assembly - $2969
  • (511cid stock bore / 518cid 0.030 over)
  • 4.5inch Stroke Forged Crankshaft
  • Forged H-beam Connecting Rods
  • Forged Flycut Pistons
  • Rings & Wristpins
Stroker Kits Video
vortec 8.1L 511 stroker kit
Raylar 511cid Stroker Marine - $8999

Our popular 600HO kit, stroked to 511cid thanks to a 4.5 inch stroke crankshaft. Our 511 marine performance package makes 625 horsepower & 660 ft-lbs of torque.

  • BigPower Aluminum Cylinder Heads
  • BP-206 Max Effort High-Lift Camshaft
  • CoolGap EFI Intake Manifold
  • Billet Throttle Body
  • 1.7 Ratio SS Roller Rockers & AFN nuts
  • ARP Re-torqueable High Strength Head Bolt Kit
  • Cometic MLS Head Gasket Set
  • 4.5inch Stroke Forged Crankshaft
  • Forged H-beam Connecting Rods
  • Forged Flycut Pistons
  • Rings & Wristpins

Supercharged Marine Performance Parts

Please note: Our engine kits do not include superchargers.

496 mag superchargerRunning boost on your 496cid engine? The stock hypereutectic pistons are not built to handle the high boost levels associated with many supercharger kits. We routinely see engines with cracked, chipped and even shattered pistons which resulting in catastrophic engine damage. Our stage 2 kits come with fully forged components, ensuring maximum reliability and performance in supercharged marine applications.

mercury marine supercharged mercruiser 496 performance parts
650 SRC / 496cid Supercharger Stage 1 - $4459

Our stage 1 marine supercharger performance package bumps the 496 / 8.1L to 650 horsepower & 675 ft-lbs of torque.

  • BigPower Aluminum Cylinder Heads
  • BP-111S Supercharger Camshaft
  • 1.7 Ratio SS Roller Rockers & AFN nuts
  • ARP Re-torqueable High Strength Head Bolt Kit
  • Cometic MLS Head Gasket Set
  • *Supercharger not included in kit.
mercury marine supercharged mercruiser 496 performance parts
800 SRCHO / 496 Supercharger Stage 2 - $5999

Our stage 2 marine supercharger performance package bumps the 496 / 8.1L to 804 horsepower & 824 ft-lbs of torque.

  • BigPower Aluminum Cylinder Heads
  • BP-207S Supercharger High-Lift Camshaft
  • 1.7 Ratio SS Roller Rockers & AFN nuts
  • BigPower Forged Flycut Pistons, Rings & Wristpins
  • BigPower Forged H-Beam Connecting Rods
  • ARP Re-torqueable High Strength Head Bolt Kit
  • Cometic MLS Head Gasket Set
  • *Supercharger not included in kit.

Keeping Stock Iron Cylinder Heads?

The stock iron cylinder heads respond very well to our 496 Roller Rocker & Camshaft Swap Kit, and modified intake manifold.

vortec 8100 8.1L 496 camshaft swap kit
Roller Rocker & Camshaft Swap Kit - $969

Raylar's full-roller camshaft kit for iron cylinder heads reuses stock head studs and fits under the stock valve covers. Includes the BP-203 camshaft and 1.70 ratio stainless steel roller rockers.

  • Kit Includes:
  • BP-203 Stage 1 Marine Camshaft
  • 1.70 Ratio Stainless Steel Roller Rockers
vortec 8100 8.1L 496 headers
496 Marine Header Shootout

Full Throttle Marine dyno tests a series of header options on a 496MAG HO. After installing our 525HO / 496cid Stage 1 marine kit they made 553 horsepower @ 5400RPM!

Header Shootout / Raylar 525HO

Want Even More Power?

Need A Tune?

We don't offer computer tuning, but we've met lots of good people who do. Check out our tuner list to find a tuner in your area.

496 MAG Computer Tuning

496MAG Stage 1 MAKES 550+HP

Full Throttle Marine dyno tests a series of header options on a 496MAG HO. After installing our 525HO / 496cid Stage 1 marine kit they made 553 horsepower @ 5400RPM!

Raylar 525HO Makes 550+HP!

Raylar Marine Stage 1


Raylar Marine Stage 2


Cool Gap Intake Manifold

mercruiser 496 intake manifold

The stock intake manifold can’t meet the air flow demands of your Mercruiser engine in performance applications. Our Cool Gap intake manifold has been engineered for one purpose, maximum airflow and power output in marine applications. Our intake manifold incorporates long, high velocity runners to provide excellent low and mid-range torque levels and a large plenum volume to satisfy the demand for more air at higher RPM’s. Our design keeps the incoming air fuel mixtures cool and dense, producing more power and torque over the entire power band.

  • 4 Available Throttle Body Openings
  • 78MM (3 bolt / LS1 style)
  • 80MM (Ported 3 bolt / LS1 style)
  • 90MM (4 bolt / LS2 style)
  • Unlimited Edition (Dual 1000CFM Carb-Plate EFI)
Intake Manifold Video

How Much Air Do Raylar Heads Flow?

mercruiser aluminum cnc cylinder head overlay vortec cylinder head

Raylar Big Power cylinder heads out flow every 496 / 8.1L cylinder head on the market. Our combustion chambers promote a more even burn, increasing engine efficiency, fuel mileage, improving driveability and reducing detonation in forced induction applications. Check out the flow numbers for our standard Raylar CNC heads and our special-order CNC Extreme cylinder heads using the link below.

Cylinder Head Flow Comparison

Mercruiser 496cid Cast Pistons Break

stock vortec mercruiser piston damage

The stock 496 / 8.1L cast pistons are not designed to withstand the forces of extreme endurance use. We routinely see engines with cracked, chipped and even shattered pistons which result in catastrophic engine damage.

"Header-Proof" Ceramic Spark Plugs

vortec 8.1l 496cid ceramic spark plug wires for engines with headers Ceramic Spark Plug Wires - $340

8.1L engines with short and long tube headers routinely melt stock plug wires and even performance spark plug boots. Ceramic spark plug wires eliminate burnt spark plug boots in boats, trucks, hot rods and RVs. If you've had this problem before or don't want to worry about it in the future, check out our 45 degree ceramic plug boots which are rated to withstand extreme temperatures up to 2000°F!

Ceramic Spark Plug Wires
marine engine performance parts