Thanks everyone, appreciate the feedback.
whitesatinmopar - if your wife can manage, then I'm sure I can too! Actually, watching the movie 'Death Proof' by Quentin Tarantino - the girls driving the '70 Challenger in that aren't any taller than me (I know for a fact that the girl driving is smaller) and they seem to fit the car perfectly. Maybe I'm just being stupid. I have seen tall people driving these cars and they always look a bit squashed, so maybe I'll be just right!
That's quite a collection of Cadillacs Fleet 500!
Aussie Challenger - thanks - I'm definitely gonna get to a show here in the UK next year and charm my way into an E-body! I'd better warn them to take the keys out of the ignition first, though - that would just be too tempting...
Hopefully I won't need spacers - turns out the head room is about the same or less than a Ford Fiesta, which I drive at the moment. No problem there - it's a pretty small car. I think I just haven't realised that whilst the cars are pretty big (Cudas seem to be more 'normal size' - they still are a lot lower than most of the cars on the road.
Thanks again, all!