^^^Thanks for the interest. Hopefully this project will move along a little faster.
Here are the pictures I took for the engine crank swap.
First pic is the 250 crank and the biggest bearing. It is a roller bearing with inner and outer races. It is impossible to get the inner races off without destroying the crank.
Second pic is the 350 crank and one of the main roller bearings. They are the same size both sides, so I can machine the case to fit with one setup on my mill.
Next are pictures of the cases each side and looking into the bottom case. You will notice that one dowel alignment hole is off center, so I'll have to re-drill one hole for center as both 350 main bearings are center pinned. Should be easy peasy.
On the second pic of the case, you can see the caliper is right over the lower edge of the top end oil feed. There is a shaft that goes in there and extends to the out side of the clutch cover where it picks up an oil galley from the oil pump cavity. I should be able to just grind that shaft flat enough so that it rests on the outer race of the main bearing.
This crank will give me a significant stroke and about 305cc all by itself. I'm also looking into a bigger bore as well to get me into the 335cc range.
More to come as it happens.