petrol gearbox onto 1.9n/a...easy or hard

[oldiguana]

eyup ducks,my last post on my gear problem was a little inconclusive so ive done a little searchin and here goes,my van has a gearbox code "acp",its a 1.6 box with a 1.9n/a bolted to it,45mph and its ready to change gear but its already in fourth.so ive found a gearbox with the code abd from a petrol van,my acp final drive ratio is 5,83 and this other box has a final drive ratio of 4,83.if i fit this box will it make my cruising speed a lot higher for the same sort of revs?if so how much,,if so what is involved in changing it,ive heard that i will need to change the bell housing and the input shaft,any ideas,difficulty factor 1-10,as im running out of time and marlady goes newquay in it in 6 weeks.............................................. or am i better off changing my 185r14's for some 205 8o 15's...........

[angry vanagon]

1/2 hour job plus gasket to swap diesel bellhousing to petrol box will improve gearing a lot my tdi van has a 4 speed 1.9 petrol box in it 3500rpm in 4th is about 65mph on standard tyres