The only cars I can recall having trouble with top speed have been older EEC IV's. They are limited to 127.5mph. The rest I always turned up. The highest you can turn them up to is 255mph and the hightest rev limit is 12,400 in case you were curious. Not much chance of hitting that.
The problem I think you may be having is that you are hitting the rev limiter beforet the shift. Which means you would be stuck in 3rd gear.
