As usual, progress is slower than imagined.
Cylinder head ready to go, patched up to not leak any coolant.
Cracks in block TIG welded, but stress (of detonation and of welding) caused #2 main bore to be out-of-round and oversize. So I used my "pseudo align bore" contraption to bore it round again, at .030" oversize. The #2 main cap isn't distorted, so I'll just use .015" brass shim stock under the block's #2 main bearing half.
Instead of sourcing a smaller blower, I'll run the 14-71 very slowly- 19% of crank speed. This required building a jackshaft for two stages of belt reduction drive, which is ready to go. 30mm wide belts in place of the original 3".
The crank is still at Moldex, don't know yet if it can be used.
Regarding the ugliness in the photo- the stresses destroyed the tight press fit of the lower ends of the steel sleeves, so a bunch of JB Weld was needed to close coolant leaks.