04-05-2020, 10:41 AM
I think there's more than one issue at play here. I can't say whether it's distortion or whether they were bored out of line in the first place, but the C/M is often not quite in line with front and rear to begin with. There's also distortion of the thin crankcase upper deck as it is clamped up tight to the cast iron block - this may take various forms depending on the state of flatness/ cleanliness of both. The original A7 studs are a tug o'war fight between block and bearing and will clamp differently depending on which is done up first. Dave may well be right that the individual components (c/m housings but also potentially front and rear bearing housings) may mess things up if chopped and changed. Plus of course not all cranks are straight...