Aluminium block

Dutra tried to make a "deck" on one somehow.....I don't know exactly how he did it, but it didn't work. It ended up being a mess......that said, how else you gonna find out? I'm sure, being aluminum, there's a way to do it, but boy, talk about a cost outlay. What would you use? 5/8" 7075 plate? 6061? I don't know "much" about aluminum. I guess you'd need to determine "what" the block is made of and try to find the same. Even a very gifted TIG welder would have to be careful alternating back and forth so as not to over heat and warp the cylinders. I've always thought it might be interesting to bore the cylinders completely out and go with a slide in cylinder, similar to what older tractors have. They just basically slide in with your hand and the head holds them in. It would be a very costly and time consuming operation.....unless of course you could do it all yourself.
To my knowledge...you cannot sleeve one.
Just looking at one in front of you...you would immediately 'see' the problem. The aluminum isnt thick to start with.

That's why filling and maybe some wax to make internal channels to cool some.
Most of the heat is up at the top and the Chamber anyways so it's like the last inch or two of the cylinder that really needs water and unfortunately that will have to be filled. Chicken wire, block fill and some candle wax or something to melt out and leave a coolant passage around the cyls