I recommend: stop using pi and borrow a digital caliper. I could be wrong, but I've never heard of a vintage '70s Italian bike using that size post. This MIGHT be a size you'd find on a Mtn. bike with OS tubing, but I think you have an inaccurate measurement, try fitting a post you know the size of (say with a 27.2 clearly marked on it) and see what goes/no-goes. I recall there was an early European cottered crank made of alloy, but it was a rare bird cause it really didn't hold up. Can't recall who made it: Nervar? TA? Durex? Somebody will chime in...