OK. Just got off the phone w/ some guy at GE aerospace that recommended I use his epoxy for my latest dilemma. With the sleeves installed, head gasket sealing now becomes my immediate concern. A copper head gasket was gonna be my go to, but hours on the phone has me changing directions, and deciding NOT to use a copper HG due to potential water leaks at some time or another. O-ringing the block would put said potential O ring on/off the sleeves, so there is also a possible source of compression escaping, and resulting in some sort of failure there as well. Cometic recommended a custom MLS gasket, but could not give me a real good sense of assurance that the 150.00 HG wouldn't fail at 18psi either. That said, and based on my conversation w/ the rocket scientist at GE today coupled with my concern for what could be a potential series of water leaks has brought me to the decision to forego a head gasket altogether, and.......get this.......... Glue the head on w/ this dudes space shuttle re-entry tile adhesive. Now I know what you're thinking,...Glue-ing the head on??? Yeah I was skeptical too until I talked with rocket dude for about an hour. Think about it. You assemble an engine w/ the ultimate goal of keeping the thing together. Building it w/ "zippers" so it can be opened up later seems like kinda dooming the engine to fail at some time in the future based on the "temporary" solution a bolted on head w/ a gasket in between actually is. If the engine was in effect "solid," and the tune was carefully "snuck" up on, why would anyone ever have to worry about the what if's, and use a bolted on head w/ a head gasket. Once running at peak efficiency, why would you need to worry about being able to remove the 800.00 pistons, and 1ooo.00 camshaftand lifters out of your irreplaceable engine block? So,...I'm gonna use GE's aerospace solution to actually holding on those heat reflecting tiles that adorn the nose of the space shuttle. Rated for exposures of -460 degrees farenheit ( absolute zero), to well over +2500 F ( re-entry temps) the glue GE aerospace uses has to be able to deal w/ the thermal expansion those tiles go through every trip into space. Also able to tolerate exposure to a butt load of freally scary toxins, corrosives, and liquids,...dude was not concerned about exposures to fuel, and oil. All while being able to hold those things on at escape velocity makes me more than confident that they'll be able to hold my weenie little head on my 200 degree engine. The guy sent me a link of the stuff actually applied to a piece of .125 thick aluminum where they were able to melt the aluminum around the glue, but the epoxy did not fail. Conversely, they applied the stuff to ordinary aluminum foil and were unable to get the epoxy to separate regardless of the impacts they subjected it to. The only drawback? The price. At 200.00 an oz. ( I should only need that much), it's just a tad more expensive than your everyday JB weld. so I'm sold,...I ordered 2 ounces today Here's a link: http://www: youreallydidntthinkiwasseriousdidyou.com You'll never get the 5 minutes back it took you to read this.