Originally Posted by
CliffordK
I picked up an E-Bay frame. It was supposed to be a Master, but I'm thinking Nuovo Mexico.
Only Downtube is fluted. It also has an octagonal fluting, while the Masters seem to have a square fluting.
It must have been early in Colnago's using fluting to strengthen tubing.
Okay, maybe another piece to the puzzle. It's my (very limited) understanding that there was a good amount of experimentation/variation between the earlier frames with shaped tubes.
The OP's pics are close to my '83 Nuovo Mexico with exception to the top tube. A top tube replacement doesn't feel likely to me, but that don't mean much. Do you have the bike in your hands, or are you still dealing with a seller? It certainly looks authentic from the few pics if that's the question.
I'll see about a better pic for comparison later on.