R40-C: How would you do it?

[wuzak]

Yes, I'm thinking of something analogous to the DB603.

How so?

The DB603 had an increased bore (12mm) and stroke (20mm) compared to the DB601, from which it was supposedly developed.

It was longer - by some 888mm/34.8" and weighed some 230kg more.

I don't know that any of the DB601 was carried over to the DB603.

More likely that the DB605 was a DB601 with bigger bore (4mm). Its length increased too, but I can believe it could have shared the same blocks/cranks/etc as the DB601.

An alternative to save development time was a simple scaling of the base design. The H/Buzzard was a 6/5 scale of the F/Kestrel. And then detail changes were made to complete the design.

 

[tomo pauk]

Scaling-up is a different thing than over-boreing.
DB-603 can be regarded as a scaled-up DB-601, while DB-605 is over-bored DB-601. When something is scaled-up, all the stuff grows up, including block, crankcase etc.