I did exactly that...replaced a Volvo MD7B with a Volvo 2003 engine.
MD7B engine...if my memory serves me correctly has a a 7 degree downward sloping transmission
....other than that it is the same as the MD7A.
The 2003B model also has the 7 degree downward sloping transmission
.....which is why I chose it.
No, the engine mounts are different.
What I did was make a wood
mock up of the 2003 engine, so I could be sure the new engine mounts would line up correctly with the existing shaft.
You will also have to switch out the props.
Like other's here, I have developed a strong love/hate relationship with these engines.
Yes, I made some wood
runners ( an extension of the engine mounts) so I could slide the engine out of the engine compartment to the companionway
, then strapped a 4x4 post to the boom, and lifted the engine out with a block and tackle. Once in the cockpit
, I re-positioned the engine to the end of the boom and swung it out to the dock
. New engine went in the same way.
I don't think either engine is made today....I know the MD7B certainly isn't. Mine was raw water
cooled. It was a pain in the arse. The 2003 has a heat exchanger