Do people really replace push rod tube seals like that? I would highly recommend taking the cylinder off and replacing the O-rings, cleaning the sealing surface and applying some Durko, adding a cylinder O-ring if it doesn't have one and has the recess for it. I would clean the combustion chamber too and re-align the rings. Remove the lifters too and check for pitting. Of course, before I took it apart I would do a leak down test and see if any valves are leaking and take care of that while I was there if need be. Myself and others I have known use to torque down heads to 28ftlbs no problem until I heard of everybody else stripping them. I now torque them to 26ftlbs per a BMW service bulletin. The bulletin was about reducing cylinder distortion on nikisil cylinders, not pulling the studs but . . . . I put 106,000 miles on a LS. Lots of fun! Good handlers but my setup always under steered. Siebenrock makes a cam for them. I would like to try raising the CR, a cam, and some carbs on one. Personally, I wouldn't go with a bigger bore. It's already short stroke enough IMO at 1.33:1. The same as a R100. And the shorter cylinders are my favorite part of them so I certainly wouldn't want to put a bigger engine in.