Yes there were big bikes slower than 2:14s in the 4 hour but they still had good speed down the straight for the most part and you only had to worry about the slower riders in the corners where speeds are slower anyway, most of us don't expect to come out of the kink on to the front straight and find a rolling chicane sitting there.
I was scared out of my gourd on the front straight on the 250s and that was only a half hour.