Well, i found a candidate for bedplate duties, hyundai alpha 2 with 82mm bore pitch, I hacked the water jackets and 3/4 of the barrels.
The remaining crank tunnel weighs in at 18kgs, a big lump.
I followed this approach as our (aussie) hillclimb rules state the only restriction is to be based on a production block. The blocks id and numbers are all present, but the terminology changes into a bedplate, with an upper 75 deg V cylinder block to be cast and machined.
Ship builders term the bedplate as a block, so it can be argumentative.
Anyhow, other candidates were 4g15 iron or GM 1.4 GSE alloy, GSE's are were released in 2007 and are still quite expensive. The Hyundai G4ED complete cost $50 (bent valve).