The 65 is all original except for the four foot long glass packs installed in probably the 70's
, oh and my lowering it 2 inches.
My 58 on the other hand is running a 390 with a cam and eldebrock intake and carb, stock manifolds with custom exhaust and disk brakes with a bigger front sway bar.
The 58 does feel maybe a little bit stronger than the 65, but I wouldn't say either one have very exciting performance. Surprisingly the 65's brakes are still better than the Wilwood's I installed on the 58.
Neither handle very well, but I would say the 58 with that bigger front bar does feel better.
More people know what the 65 is than the 58, I hear alot of people that have no idea what the 58 is.
I see the 65 as really nice and comfortable to drive, it's quiet, has a/c, the 58 is loud and in your face. I think the 58 is more unique , bold styling, and masculine, where the 65 just exudes class
I personally not sure I can pick one I like over the other.
I can say that most of my friends tell me they all the like the 58 the best of all the cars I own and with my disease I have a quite a few.
My opinion is you can't go wrong with either one, you don't see them very often and they are built very well.
I was going to post a photo of mine together, but I don't have one....