Changing Chrysler i/b to Chevy i/b process

Edcardinal

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Oct 15, 2020
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Been looking at a few boats and most of them are 70s all glass Luhrs or Silvertons (I prefer Luhrs) 25 or preferably 28 foot single screw boats. And so far they are all CHRYSLERS with Walter V Drives. What I want to know is how easy is it to change them over to 350/5.7 GM motors which I know well and are easy to get parts and work on for me since most of these motors are 20-40 years old. Would I need adapters to mate to the GM motor to the CHRYSLER transmission bellhousing and are these standard rotation engines like a car or are they all reverse rotation?
Any insight whatsoever is greatly appreciated.
Thanks.
 

alldodge

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Mar 8, 2009
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I'm finding adapters, and do think finding a Walter to GM should be available. Barr makes many of them

The issue with reverse rotation RH, could be the issue. You can still get a RH cam but its custom in most cases. If the transmissions are direct drive and not V-drive this will be an issue. There are no LH conversions for a RH trans. There are conversions for reverse rotation Walter V drives.

My suggestion is to stay clear, or replace everything on the RH side with a Velvet drive or other like a ZF and reconfigure
 

Edcardinal

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I'm a bit confused. I believe these are probably velvet drive transmissions with WALTER V-drives. I'm just not sure of the rotation of the motors or if i find the correct rotation motor WHERE to find the adapters from CHRYSLER to GM bellhousings.
 

Scott Danforth

Grumpy old guy who plays with boats
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Jul 23, 2011
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Kennedy adapters makes engine/trans adapters. However my suggestion is to buy a much newer boat, or as AD pointed out, upgrade motor AND trans.
 

alldodge

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I'm a bit confused. I believe these are probably velvet drive transmissions with WALTER V-drives. I'm just not sure of the rotation of the motors or if i find the correct rotation motor WHERE to find the adapters from CHRYSLER to GM bellhousings.

Water is a trans and gear box. If your boat has both a velvet and a Walter trans that would be new for me. Not saying it doesn't, just would be new to me

There are places that will build a reverse rotation motor, but the thing that make a LH to RH is the cam. You can take a standard LH motor and turn it into a RH by replacing the cam
 

Scott Danforth

Grumpy old guy who plays with boats
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the GM motors simply kept the cam and drove it with a gear vs a chain, so the cam and oil pump rotated in the same direction. The Chryslers in the boat would have had different cams. in addition to the cam / timing drive, the directional knurling on the oil control surface for the front and rear seals are also reversed if the crank is a 2-piece RMS design.
 

Edcardinal

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Water is a trans and gear box. If your boat has both a velvet and a Walter trans that would be new for me. Not saying it doesn't, just would be new to me

There are places that will build a reverse rotation motor, but the thing that make a LH to RH is the cam. You can take a standard LH motor and turn it into a RH by replacing the cam

Yea, the BORG WARNER Velvet drive is the trans and hooked to it is the WALTER V-drive facing the bow.
If the boat had no V drive the motors would be further forward and the flywheel would instead face the stern with ONLY the trans and motor on an angle.
 

catman977

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Jul 7, 2020
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Good Info Scott, especially the Knurling on the Crank Shaft, for the reverse spiraling, to keep the pressure off the rear Main seal. Read where a man bought a new crank shaft for his 440 Chrysler, it was a RH marine Crank. He tried everything, to keep the rear main from leaking, until he discovered the problem with the reverse Knurling. I have two 440 Marine Engines, with Velvet Drives, one Engine is a RH, and also it's Drive, is set up for the Reverse Rotation.
 

kenny nunez

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RH rotation engines also have the pistons reversed on the rods. While the engine will run you will have idling problems and the pistons will not last long as the thrust sides are not on the load side.
 

Edcardinal

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Oct 15, 2020
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I picked up a FULLY FWC 1994 MARINE-POWER 5.7 GM VORTEC engine out of an EGG HARBOR Right hand rotation. Only issues I see so far is the motor has a straight drive trans hooked to it so the engine was up by the seats with the pulleys facing the bow and trans facing AFT. So it needs to be turned around and I guess the risers turned backwards, and the oil pan replaced with the SUMP on the other end I assume. But not sure about the oil pump pickup if it needs moving, or how to move the riser cooling lines. Also if the smaller VELVET trans will hook up to this bellhousing adapter.
 
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