Thank you all.

I forgot to mention that I also received the matching color Silca/Campy frame pump with Masi engraved on it. The original owner also gave me the one page, color brochure that was circulating at the time.

http://masi.gregfletcher.net/masi/html/broch1.html

I measured the downtube (I can't believe after all of these years I never measured it) and it is 52 c-t-c but is marked MC54.

This bike has not been wiped or cleaned since I got it about maybe 20 years ago. You can still see the original Campy grease that squeezed around the bottom bracket axle. No evidence of dropping the bike on the brake levers. Original Campy brake hoods that still look brand new. The only mystery are the mismatched rims. The front wheel must have been damaged or stolen but there is no crash evidence on the frame, brakes, rear derailleur and pedals and same Campy levers and matching hubs

And, the rear der is Pat 73!

Where is that immaculate, low mileage, all original 1974 58cm Masi Carslbad, twin plate looking for a new home?