Here's the limo. Look yourself at the seats. Or do you need the Senator from Scotland to actually sit in the limo to demonstrate it for you?
Here's two men sitting in the limo, showing the relative heights:
Can't you see in this photo how much lower Connolly is sitting than Kennedy?
More limo photos here: http://www.jfklancer.com/Limousine.html
But why wouldn't Specter bring up the difference in heights as to why Connolly's wounds were where they were?
(I was 5 at the time, but I remember glancing through my parents' copy of The Warren Report years later.)