RE: DROPING THE TOP
Yep, they can easily add 200lbs to a car.
I am guessng but back in the day, they probably did't worry about stiffening up the chassis when they took the top off.
Back then convertibles were mostly mechanical, now they are electric.
Designing in impact resistance was not a issue back in the day. Without a roof the sides are weaker and have to be reinforced, etc, etc..
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