I can still see the factory hone marks in the cyl walls. 100k is nothing IF it's had any type of care at all. The roller lifters (providing they are good to start with) will be fine at .530 lift. I will bet you'll find a bad cam bearing or two. Easy to replace. Then I'd just spin the oil pump over with a drill and primer and see what pressure it has. If the pressure is good, I'd leave the bottom end alone. Throw your new cam and timing chain in it. Make sure your valve spring match the cam
