there always will be a lot of discussion on this, just like the classic disputes some people will be forth and others against with equal strengths and the same ammount of reasons
i think that the answer is most inside you than outside, just because technically both solutions are possiblee,... would you like to preserve the originality of the car, knowing that the result of your work is a flavour a feeling of what these cars behave just 40 years ago ?, or you just like the envelop, the body, and you prefer a more powerful mechanics below ?
in my case, maintain it original !
cheers