Repowered HR Rasmus and HR41
We repowered our Rasmus with a VolvoPenta D2-40 and have been very satisfied.
Note that the original MD21 is often said to be a 75hp engine - it is, but under entirely irrelevant conditions (high rev, short time etc). Ii is actually a 45hp engine!
Keeping this in mind, you may be happier going with a "small" engine. With our D2-40, we were happy because;
1. easier access for service
2. lower fuel consumption (we average 1.7 liters per hour)
3. save more than 100 kilograms
4. cheaper than a big engine
5. we make 7 knots at 2100 rpm (burning about 2 liters per hour
The Vetus M4.17 is the same basic Mitsubishi block as as the VolvoPenta D2-40. Other brands also use this base engine. Note however that output and cylinder volume differ between different conversions of this base engine.
We were so happy with the D2-40 (which is a 1500cc engine giving 37hp) that we even repowered our Hallberg-Rassy 41 with the Vetus M4.17 (which is a 1750cc engine giving 42hp). Both the Hallberg-Rassy Rasmus 35 and the HR41 originally had the Volvo Penta MD21.
You can find more info on our site www dot syanna dot se
Good luck with your project! Please post back once you have completed the swap.