Jonesy, I like the 'Ice Cold, MN ) as I grew up in St. Paul!
The assembly manual should have dimensions. In reality, I've seen so much variation in original cars that there is probably some leeway. We're talking 60's production lines here. At Carlisle, I saw original Yenkos with more variance than I would have thought. Anyway, I would go by factory specs in the manual.
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Rick Dorion
69 RS Conv,355,M20,4.10's and I don't worry about stone chips ( yet ).