No two ways about it, aside from intake valve leaks, I had gasket failure. What I have determined is : when I assembled the motor, the 2.25 intake valves hit the side of the eybrow, so instead of flycutting the relief wider, I used .030 offset dowels to move the head outward. No problem, except, when I installed the head bolts, the bolts were very tight to the inside of the head. I figured this would not be a problem. What I now realize is, I had inadvertantly side loaded the head bolts causing the heads to have an axial preload. Didn't give it a second thought at the time, but what I suspect is I increased the load to the point where when the motor went through the heat cycles, the heads moved. alum head/iron block combo will do this normally, but in this case, I made it worse. It's obvious the dowels are at best just locators, not precision fit. Worse part, the remedy was simple. All I probably needed to do was hit the inside of the bolt holes with a rat tail file, or just drilled the head bolt holes slightly larger. Or done correctly, flycut the pistons!!! Know better next time (this time).

PS - this sucker is going to fly next trip out.

I just read this on the other forum and went back and it was moved.You two are getting a work out this winter.