
Originally Posted by
David88vert
In 4th, you have a 1:1 transmission ratio. If you have 5th, that is OD gearing. OD is either 0.864 or 0.773. We will assume it is 0.773 to give you the benefit of the doubt. I'm giving you the benefit of the doubt thinking that you have the 1980 transmission and rear end, rather than the 79, which is worse.
Stock tire size was 195/70 VR14.
If we calculate based upon that, we find that you would be running 113.7 mph at 5K rpm - and that is if you have zero wind resistance, and no coefficient of drag. You would have to do 5700 rpm to reach 130mph utilizing your OD. Your 4th gear couldn't reach 130mph at even 7K rpm.