Higher differential gearing?

[philwalters]

hi I have a 1977 M1 Transit van Petrol 2l (essex V4 ?) single axle single rear wheel with incredibly low gearing and Ive heard a MK3 diff or crown wheel (?) will increase the gearing/
Any info appreciated as 80Kph is noisy and 100 kph is deafening?

[dumper]

On my mk1 I replaced the v4 with a 2 L pinto it was running a 5. something diff and mpg was 18 to 20 mpg the local Ford dealership was moving and had a clearance sale and I got a new 4.62 and it was lovely and quiet but the mpg did drop to 15 mpg so I put the 5. something back .Later on I fitted the 4.62 diff into a 1986 120 mk3 so you should be able to fit a mk 3 diff in yours but personally if you can find one I would fit a 4 speed box with overdrive that will fit without modifications to the transmission tunnel I fitted a lwb one in a swb all I had to do was get the propshaft shortened and a ignition feed to the gearbox and I may have had to fit a longer speedo cable .
And if you don’t get the gearbox rear X member you can modify it to fit.