GM 496 Base Engine • Cast Iron Heads • Flat Tappet Cam
MBP4960CT - Marine Engines - GM 496 Base Marine Cast Vortec Heads
HP & Torque: 460 HP / 515 FT LBS
Compression Ratio: 9.0:1
Cast Iron Heads
Forged Pistons
Flat Tappet Cam
Cast Steel Crank
Part #: MBP4960CT


4 Bolt Main .060 over block
two piece rear seal
drivers side dipstick
Square and parallel decked
Align honed main bearing bore
Cylinders honed on computer controlled machine to within .0002 straightness and roundness
Cylinders are sonic tested for thickness

Rotating Assembly:

New cast steel crankshaft internally balanced
New 4340 forged H-beam connecting rods
150,000 psi rod bolts
Forged flat top Pistons
Hastings moly rings
Rotating assembly balanced to within 2 grams
Melling high volume oil pump
Heavy duty double roller (high performance) timing set

Cylinder Heads:

GM cast iron oval port cylinder heads with screw-in studs and guide plates
1.509 dia. Valve springs w/ damper. Hardened retainers & keepers. 2.25 swirl
polished intake valves, 1.88 swirl polished exhaust valves
Elgin hardened push rods
Long slot rockers with postitive lock adjusting nuts

Cam Specs:

Cam Type: Flat Tappet
.544 Intake .547 Exhaust
226 Intake / 236 Exhaust duration
@ .050 - 112 degree lobe separation

Ignition Timing:

34 Degree Total

Also Includes:

Marine intake manifold
Chrome valve covers
Oil pan
Brass freeze plug
Dyno test results shipped with engine


12 month unlimited hour on pleasurecraft only. No warranty on commercial use.

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