so i have a 76 bay with a reco 1800 only 1000 k's clocked and a 1600 gearbox my acceleration is amzing though i can only do 90 comfortably , i have the biggest tyres i can get aswell ,

is there any other way to get a higher top speed out of my van without getting a new gear box?

Wheel alignment is perfect?

Tyres properly inflated? (maybe run couple psi more)

Rear drums properly adjusted? (no dragging)

Just trying to think of energy 'losses' to eliminate with current setup.

If engine top end was a bit more frugal, you'll be ok. Sounds like you got plenty of bottom end to trade off for some higher end power. Check to make sure dissy timing not too retarded to gain mild top end HP.

More free flowing exhaust for top end is other option, as is carb upgrade.

You will need a new gearbox or very large tyres (Baja style)
An 1800 gearbox with a 1600 4th gear is what I have and sits on 3250rpm at 100km/h