i have two rear sierra diffs one is definately a 3.62 ratio,the other has a whole host of numbers on the tag but indicates its a 3.92 because the only other numbers are1374 and i dont believe that a 3.74 ratio exists(correct me if im wrong please).but has 83BGJT392 also 0on the tag..whitch one will be the best to use with a 2 litre engine instalation..any advice would be great

if you want top end, use the 3.62:1 diff
if you want acceleration use the 3.92:1 diff


i'm gonna be running a 2 litre turbocharged engine and will be employing my old XR4x4 3.92:1 lsd

the 3.92 diff i have has larger diameter driveshaft holes and the diff is wider than the 3.62diff i have,are they both the same overall width and whitch will be best suited to my indy with a 2 litre motor??????????

Hello Dave
Hows it goin?
How far have got in a week?
It sounds like youve got 1.6 and 2 litre
diff by the sound of it.
Skippa D
PS got me pot off the other day, still cant walk!

I'm using a 3.62 diff in my 2ltr zetec Indy. With the MT75 ratios first is still low, but 2nd is just right as is 3rd. With the lower ratio diff 1st will be very low with 2nd acting more like a normal 1st. I would'nt worry too much about top speed as I doubt you will spend much time at it, sevens are all about acceleration.

thats what i thought dont think ill be traveling at 80 mph plus very oftern with no screen,what about the type 9 box will that be suited to that diff?????