I'm working on an aluminum motor also, mine has plenty if sediment in the bottom of the water jackets but the tops of the cylinders are nice. I haven't gotten into it far enough to determine if it's rebuildable or not but so far it's promising...
If the top of the cyl could be built up, welded without warping the **** out of it...it would cure the weeping issue most have around 60-70k miles.
Dutra did the flange deal...that was expensive and them he blew up the bottom end using the cast crank and he might have done something else with the oil squirt holes pointing in the wrong direction. Cant remember.
But welding or filling the block top half and or limiting the coolant flow in the process to just the exhaust side of the cylinders with wax and some copper pipe for passage direction to head.... I was thinking a lot about it 12 yrs ago before I did the stroker stuff.
