Replace VP 2003. With what, where and how much?

[Tranona]

We had a 2003T, 7500 hours on it, still good running, no oil consumption, but oilcooler corroded, gearbox whining, very expensive spares (if available), etc. After the decision to replace we found that the 2003 is a very small engine and most engines wouldn’t fit in. Only the Yanmar 3jh5 was small enough and no big changes to engine bed needed. Did need to change prop and exhaust though.
Should have done it earlier.

Yes, since the Perkins/Volvo 2040 was discontinued in 2004 the Yanmar is the only 3 cylinder 40hp engine left. One of our club members has just done the same in a Malo where the preferred engine (Beta 38) was too long. Very pleased with the Yanmar though. Fortunately the OP needs a 30hp where all the competitors are much the same size and the Volvo D1 30 is the most straightforward replacement.