marine inboard propulsion

8. Marine Inboard Propulsion


Under Construction

CC 283 Marine inboard

The Chris Craft 283 marine inboard engine, 185hp version, was the next step to a marine converted (Small Block Chevrolet) SBC V8 platform. It was interesting that Chris Craft took that decision, because their latest engine, the MCL/WB family, based on the Hercules 6-inline platform, was already delivering 175/200hp. Anyway, more capacity and more power was one of their ingredients for selling more Chris Craft boats.

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SBC 350 marine inboard by WoodspeeD

The reason to develop this engine, was to find a good replacement for the Chris Craft 283 in my wooden Chris Craft boats. Some of my boats do have a Hercules and other a SBC Chris Craft platform. Although, parts for both platforms were findable, but not always easy to get. When parts become harder to get, their prices go up. Some of the boats I have and most boats I have worked on, their engines were not original anyway. Some of these engines were patched with parts, that did not the marine job or were running rough.


The WoodspeeD 350 is the drop in replacement for a 283/305/327. With some modifications, you can swap your Hercules Flathead platform for W350 too. The torque for this engine is exceeding your expectations and all parts are still available. Some parts of your old engine might be reusable.

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SBC 350 CLC marine inboard by WoodspeeD

The reason to develop this engine, was to find a good replacement for the Chris Craft 283 in my wooden Chris Craft boats. Some of my boats do have a Hercules and other a SBC platform. Although, parts for both platforms were findable, but not always easy to get. When parts become harder to get, their prices go up. The boats I have and most boats I have worked on, their engines were not original anyway. Most of these engines were patched with parts, hat did not the marine job.


The WoodspeeD 350 is a drop in replacement for a 283/305/327, but equipped with CLC (Closed Loop Cooling). CLC is developed not to pickup water for engine cooling. The entire cooling system is a high end cooling system with an electric waterpump and radiator. The radiator has two electronical controlled fans, to keep your engine cool enough. 


The torque for this engine is exceeding your expectations and all parts are still available. This engine is entirely build with new parts. We do not recommend to reuse parts.

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SBC 350 CnE by WoodspeeD

New build (2023)


Before, I could start this project, I need to select parts carefully, because some parts need marine certification according to USCG. Also, when parts are not satisfying, I should be able to change them easily. 

Since this application was 100% dedicated for marine purposes, an USCG approval would be very beneficial to retrofit this on older wooden boats. 

I have built several 350's in the past and watched the competition (Mercruiser, Ilmore etc.) for a while. You need to understand, that parts applied should bring you a benefit, not just for show reasons. Another fact is to keep the total price for this setup affordable, so this 350 can be reproduced, over and over.


Goal & Requirements


  • SBC platform,
  • around $5K of parts,
  • a cast-iron foundation (Block, Heads, Crankshaft), 
  • modern, high performance parts,
  • achieve low fuel consumption, 
  • electronic control; engine temperature, fuel & ignition, 
  • no water pick-up, 
  • pump gas compliant, 
  • high torque at low RPM, 
  • plug and play wire harness,
  • one display for monitoring,
  • low maintenance,
  • eaasy install platform in any older wooden speedboat and/or cruiser,
  • manageable device EFI & EI for different boats
  • reliable platform.

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SBC 383 CnE by WoodspeeD

New build (2023)


With the experience of the 350 CnE, I started this project for more torque at lower RPM. Also, I needed more USCG certified parts. 


Since this application is 100% dedicated for marine purposes, an USCG approval would be very beneficial to retrofit this in older wooden boats. 

I have built several 350's in the past and watched the competition (Mercruiser, Ilmore etc.) for a while.

Fact is to keep the total price for this setup affordable, so this 383 can be reproduced, over and over.


Goal & Requirements


  • SBC platform,
  • around $7K of parts,
  • a cast-iron foundation (Block, Heads, Crankshaft), 
  • modern, high performance parts,
  • achieve low fuel consumption, 
  • electronic control for engine temperature, fuel & ignition, 
  • no water pick-up, 
  • pump gas compliant, 
  • high torque at low RPM, 
  • plug and play wire harness,
  • with main display for monitoring,
  • low maintenance,
  • easy install platform in any older wooden speedboat and/or cruiser,
  • manageable device EFI & EI for different boats reliable platform.

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Chris Craft 283 (1978)

When a friend of mine bought an old wooden project boat of 1961, many years ago, I had no clue what a Chris Craft speedboat was. It was from the USA and had only experience with Boesch speed boats. At first sight, it needed new planks for the bottom, an engine rebuild, a new wire harness from the engine to the dashboard, a gas tank cleaned out, new fuel lines, a rebuild carburetor, a new fuel pump, new ignition coil, a set of points, 9 spark plugs, a temporary ignition key, since the old one was corroded, a new clutch, and an aligned prop shaft with new shaft seal and balanced prop.


We had to put the boat in the water, to see if the engine run and if leaks were visible from the inside. We let it swell for a day, and at late afternoon, we did an attempt...bang, bang, big flame out of the carburetor, keep banging, engine noise sound like lifter tick or detonation, the boat shuddering all over and water coming in via the shaft seal.


Okay, had a big job to do...engine, wires, fuse panel, mechanical gauges and fixing bottom planks and a real good bottom paint! We did not have Petit Old Salem racing copper paint, but Interlux from AkzoNobel.


When the entire bottom was repaired, it got 8 layers of paint. That was a lot of money for that time! The engine assembly came along, and all engine parts were installed. The engine got new paint too and ready to hang it back in the boat. Tested, all the lines and hoses with compressed air to see if air was escaping (You can check that with soap), I filled up the gas tank with pump gas. I had the battery already charged and a new V-belt fitted. The water pump was also rebuilt and got a new bearing with a new impeller.


So, let's crank this rebuild baby...One turn, two turns, three turns and the engine started running, a bit rough, with some bangs, but it ran.


I switched the engine off and retarded the ignition 5 degrees, but increased the gap of the contact points a bit to increase dwell, and also increased the electrode gap on all spark plugs. When I do this, the spark energy should be a bit more. The camshaft was still original, the distributor was turned ACW, so mechanical advance was a bit retarded.


I started the engine again. One turn and it runs! Yeah, 750 RPM, 50 PSI oil pressure immediately at high idle (engine was still cold), 13.8 Volt of charge, 22 Amps of current, and the coolant temp needle left zero. All gauges on the dash were working as expected. The sea cock was connected with a hose to a tank of water, and the water pump sucked up the water. The engine started spitting water and the exhaust fumes smelled like I was used to...


Great! What a sound! 10 minutes later, when the engine came at temperature, it started smoothing out more and I found out a better ignition timing point. The engine idled now, really smooth.


At that time, I had no special tools, I had to go to school... but my ears, my smell and watching for irregular vibrations were still working :-). No mechanical noises, no leaks, just a good running engine and a quiet spinning prop shaft.


I switched the engine off, took the spark plug out in cylinder #1, put a thin screwdriver in the cylinder, turned the crankshaft pulley twice to see were TDC was. After that having validated, I put a little yellow tip of paint at zero on the ignition pointer and a yellow stripe at 12 deg., on the crank shaft pulley. This engine was ready for a ride.


When I rebuild this engine, I reused most parts. All new parts were kept standard. The cylinders got 0.30 overbore, new alu alloy pistons with rings. All new valves, valve seats, guides and seals, due to two broken valve springs and bended valves.

The camshaft and crankshaft remained in their original bores, nothing tapered, reused the original bearings and seals. Entire clean-up of block, cylinder head and other parts. No doubt, to apply new cylinder head gaskets and all other gaskets wherever required, together with bolts and nuts.


This was my first Chris Craft 283 engine rebuild (1978). I had done some 4-cylinder engines before, but this engine was big!


With this project, I combined several activities to bring new life in a wooden speed boat again. I was 15 years old, loved to waterski then...


William Adrian

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