Dear Martin;

You'll need to leave it in 4th till you can drive 65+ safely, or there's a slight downgrade/tailwind situation etc.

Otherwise you'll need a lower 'rear end' ratio.

I would think it okay 'as is' with a little practice.

Good luck. \:\)

John M., I.I. #3370

"There are no shortcuts to any place worth going". -Anon