Update, I got it all together and everything went together just great. Pins fit nice in the bushings, so i have finally put an 800 topend on a 750. Went with .039" base gasket, single layer of head gasket, although the head gasket I used was from winderosa. They measure much thicker than stock gaskets so by using one layer of the aftermarket I ended up with just under 2 layers of OEM thickness. I had shaved heads already on my 750 previously which I was not aware of, so I put them back on. I used the old 800 pistons I had and installed new rings. First compression test was 130psi. With a few drops of oil down the cylinders that number went to 140. I think I should be around 150'ish after rings seat. If you want some pictures of the bushings, better than the hauck website, I can send a few along to ya.