5th Gear

I think the answer is that it would be very difficult to achieve what you want in the gearbox.

If you could just swap one cog in the box (and I don't think you could) then you would mess up the spread of the gear ratios, It would be quite odd to drive with a big jump from 4th to 5th.

A nice simple solution would be a different set of drop gears (which I think the thing could take) but these only ever existed to make the gearing shorter for track use, not longer (as far as I know).

If you really wanted to change the overall gearing then the simplest way is probably to do something with tyre & wheel sizes - but of course you will mess up your speedo / odo (and maybe other things too).

I never really understood why the gear ratios seemed just a little bit short as they do in every day use until I drove thing up & down some mountains in France/ Switzerland & Italy - at which point it all made perfect sense.

In truth, that's what they were designed for, not long highway runs.

 

Plenty to read on the subject in these threads here :

Ultimately there's no cheap easy/straightforward way to address the issue.

https://www.ferrarichat.com/forum/threads/final-drive-gears.205338/

https://www.ferrarichat.com/forum/threads/drop-gears.336710/#post-140831309

https://www.ferrarichat.com/forum/threads/final-drive-gearing-change.43891/

 

taller tyres would work-- otherwise have a custom 5th gear made and matching 4th/5th cluster gear