Silver Wraith 7.4L 400bhp

V8 Big Block Chevy 427cid

7.0L 400bhp V8 Performance Marine engine rebuilds A real master piece! Designed for the discerning owner who wants the best for his boat. It has been developed to be right at the maximum recommended BHP and torque recommendations of the Mercruiser Bravo range of legs. There should be no problem with Volvo Penta legs. Which ever drive leg is used, a propeller upgrade will be required to get both the full performance benefits and to prevent serious over-revving of the engine(s). Once fitted with suitably matched propeller(s) * you will be surprised at its comparatively frugal fuel consumption at cruise due to the much lower r.p.m required, despite quite startling performance.

Get a quote today

7.0L 400bhp V8 Performance Marine engine rebuilds Just a glance at the specification sheet will reveal a list of quality components that reads like a race engine and shows just how good a value for money this is compared to manufacturers alternatives. Like all Swaymar special series engines this too delivers loads more torque and BHP several hundred rpm lower down the rev range than its factory replacement counterpart. Specifically designed for Hi-torque, this engine is perfect for marine applications. These carefully considered engineering improvements result in a considerably faster boat but without the usual fuel penalties associated with more power due to the much lower r.p.m required.


  • Mercruiser
  • Volvo Penta
  • any boat running Chevy V8s

Only suitable for Mercruiser's equipped with Bravo legs. Can be used with most Volvo Penta drive legs.


  • Fresh water cooling system
  • Full refurbishment and re assembly of existing ancillaries


  • 1 year limited warranty,subject to the fitting of a new or refurbished inlet manifold and new cast iron exhaust manifolds
  • 2 years limited warranty when fitted with 1 piece stainless steel exhaust manifolds

Not Included

  • *New Cast iron exhaust manifold*
  • *New Inlet manifold*


5.0L 280bhp V8 Performance Marine engine rebuilds We strongly recommend to all of our customers to consider trying a 1 piece stainless exhaust system and do away with the fear of leaky cast iron ones ruining your engine. You can find more detailed information on stainless steel marine exhausts as well as independent articles written by marine surveyors on the pit falls of cast iron manifolds at

Propeller Pitch

5.0L 280bhp V8 Performance Marine engine rebuilds Depending on boat, in order to prevent over-revving, and feel the full effect of its extra torque, this engine will need to carry a larger diameter or coarser pitch propeller.

Get a quote today


Displacement 454 CID (7.4L)
Engine Type V8
Peak Torque 480 ft lbs @ 4200 RPM
Torque Range 430+ ft lbs @ 2700 - 4700 RPM
Bore & Stroke 4.250" X 4.00" (107.95mm X 101.6mm)
Compression Ratio 9.5:1
Camshaft Stage 2 - Specially developed marine camshaft - delivering more torque at lower rpm.
Major Components Steel crankshaft, forged competition con rods, and performance pistons.
Head & chamber work Reshaping of combustion chambers in cylinder heads - To improve gas flow and increase torque.
Optional Cooling System Closed fresh water cooling, Long Life 5-Year Anti-Freeze, 20 year long life silicon hoses - Protecting your engine from the inside out.
Advanced Engine Lubrication System Expertly modified oil galleries provide greatly improved lubrication to the camshaft, cam followers, gears and timing chain - For optimum engine longevity.
Get a quote today