I've just collected my donor sierra. It is a 2.0 Dohc 1990 (h). Does anyone know what diff this will be (7 or 7.5) as I'm building a tiger avon and have been told that the 7.5 diff doesn't fit.

My donor was a G reg it had a 7in diff and was a 3.64 if that helps
Jacko

The vast majority of Sierra diffs are 7". There was a 3.77:1 diff which measures 6.5" but you'd be extremely lucky to find one of those. They're even rarer than the 3.14........

Phil

My 2.0 dohc j reg estate had a 7.5 3.9 diff
its now fitted to my haynes with a modded lhs bracket.
the way to tell is that the top mount where the long bolt goes through is roughly 7.5 inches on a 7.5 and roughly 7inches on a 7 also there should be a tag to tell you the ratio
theres a list on here somewhere do a search for sierra diff codes.
but remember its possible somone could have changed it somrtime
Ray

I think that all the 2 Ltr DOHC's were 3.91. HTH Ray

those 6.5inch ones have different inner CV joints too. Its not one of those as they only came on early small engined variants.