Hi guys,

Need some help, what Cosworth rear LSD differential should I choose a 7" or 7.5"? The 7" is £150 cheaper second hand and currently my thoughts are go with a 7'. Is There any reason I should choose the 7.5" over the 7"?

Please Help

Ps Happy New Year Building to you all!!!

[Edited on 13/1/18 by sammini7]

Will both fit in your chassis?

7 inch is plenty strong enough in a lightweight car,bigger is stronger.Hence Ford used 9 inch diffs in GrpA cosworth etc.

7 is lighter and but have smaller LSD,
7.5 have more weight, but bigger LSD
cosworth 7.5 dif have bigger lobro fiting, so can be problem fiting with standart sierra or granada driveshaft - first check if fits
If LSD condition is ok - is not need go to 7.5", but car is old.... i have one car 7.5 another 7 - both not working perfect

about body:
7 -7.5 diff body main different is top muont (left size 0.5 wider), sometimes quite easy to fit

p.s. i dont remmber kg, but i can try to weight it


[Edited on 13/1/18 by fregis]

Many thanks for all your help I have identified my chassis is setup for a 7" diff

[Edited on 14/1/18 by sammini7]