Thinking of changing my 3 speed auto in my EA fairment ghia to one of the 4 speeds from an 4 speed out of an EB.

Any suggestions or recomendations on the topic work be appreciated

Do you want performance or economy????
The diff in that should have 2.77's.

Looking for both really, but performance is always good

Should upgrade to a 5 speed manual.. a mate of mine had a 4 speed EA and it wasnt much quicker off the line my 3 speed..

a 5 speed manual would be the go..

if you change from 3 speed to 4 speed you wont notice any reall performance difference except being a 3 speed and probably has 2.77 dif ratio.
so changing to 4 speed would only make it better for cruising and economy on the freeway..due to tall diff ratio with the 4 spd auto

but if you change to 4 speed auto and change your diff ratio to 3.23 or even 3.45..

you will find the car will accelerate much better and plus you have the bonus of the lock up torque converter in top gear giving you better economy

depends if you want power or economy. 4spd will yeild much better highway results and be quite smooth but wont be any faster really than the 3spd except you will have two shift patterns normal and economy 5spd will be faster but will require more suffing around. i personally would go a 4spd auto unless you are planning on making it quick