Alternator upgrade ??s

You won't be getting "140 amps" output very often. If the system is only using 40amps that's all you'll get no matter what the alternator you use is rated for. What about a factory 100a from 70s/80s?
The last couple of years of police diplomat they used a either a 90 or a 120 amp alt with that same regulator as the 65 amp unit took