my friend own a 75 bronco with Ford 9 Factory rear end... but he change from 3.50 gear ratio to 2.73( something like that... 2.7x ) using an other Ford 9 Econoline Rear end...

What kind of front end 75 bronco have?
in witch kind of car he can find out the same ratio for the front end?

 

Sorry to burst your bubble, but the front end is a Dana 44 and is not a removable carrier like the 9" rear end. No 'passenger car' had the Dana 44 from Ford. If you want to change to the 2.7X gears the front end will need to have the R&P changed by someone who knows how. also the Bronco front end is 'Bronco' only as far as the whole housing goes. The F-100 Dana 44 front end is wider.
Why was the rear end changed in the first place? Most peaple go to 4:11 for off road performance.
Good luck.
Eric



Proud owner of a '73 F-250 4x4 High Boy, 460 V8, NP435, NP205, Dana 60 rear w/Detroit Locker
And a '68 Bronco 289 v8 , NP435 , Dana 20

 

he changed from 3.50 to 2.75 ( ive checked the plate.. )
for a better fuel economy and he says its really good fuel economy than 3.50..

he use a 1975 frame /351 V8 / 3 speed trans / front and rear end from a 75 bronco but he put a 1985 Bronco II cab on it...
so.. everything is a 75 bronco except the cab...

so.. if he's looking for a F100 2.75 front end that would be okay?
or F100's dont have 2.75 gears?

 

Your friend is out of luck. No 4x4 that I know of ever came with 2.75 gears stock. The F-100 is 7 inches wider than the Bronco. NOT a drop in item. Plus it would look funny with the front tires sticking out of the fenders. you will need to change the gears themselves.
Eric




Proud owner of a '73 F-250 4x4 High Boy, 460 V8, NP435, NP205, Dana 60 rear w/Detroit Locker
And a '68 Bronco 289 v8 , NP435 , Dana 20