7.5 diff in a SS1?

Moderators: scimjim, philhoward, Lukeyboy46, erikscimitardemon, Roger Pennington

Post Reply
Posts: 135
Joined: Wed Jan 11, 2017 8:31 pm
Has thanked: 3 times
Been thanked: 2 times

7.5 diff in a SS1?

Post by Jhdelta » Fri Apr 12, 2019 7:02 am


has anyone achieved this?

I remember seeing comments somewhere that this can be done with a little help from a grinder?

i have a sierra 7" 3.6 lsd in at the moment but want to go to 3.9 and there is a 7.5 availble on ebay.

unless someone has a 3.9 7" looking to move home


User avatar
Posts: 14192
Joined: Tue Aug 22, 2006 5:13 pm
Location: Shrewsbury, Shropshire
Has thanked: 331 times
Been thanked: 265 times

7.5 diff in a SS1?

Post by CNHSS1 » Fri Apr 12, 2019 7:13 am

7.5" is a big old lump, fair bit heavier than the 7", so would give the diff cradle bushes a tougher time.
To fit your need to narrow the top section where the long bolt usually goes on an ss1.

7.5 has either 100mm or 108mm CVs, check the one you’re after has 100mm as I'm assuming that's what your 3.6 has.
Alternately, whip the diff out of the 3.6 lsd, remove the crown wheel and drop in a cheap 3.9 non lsd 7"

Racing is life, everything before and after, is just waiting--Steve McQueen
6 time Class Champ, 2006 & 2014 SSSC Champion

RIP Batmobile, await the Rise of Dark Knight 8)
Sabre 'Light Sabre' 360hp!!

User avatar
RSSOC Member
Posts: 37439
Joined: Sun Oct 01, 2006 10:08 pm
Location: Gloucester
Has thanked: 130 times
Been thanked: 948 times

7.5 diff in a SS1?

Post by scimjim » Fri Apr 12, 2019 8:31 am

3.92 is the standard ratio (the 7.5” is 3.91). I have several standard diffs available.

Jim King


Current: SE5 (8Ball), TI SS1 (snotty), 1600 SS1 (G97), 1600 SS1 (C686CCR), 2.5TD SE5a (diesel 5a), 6 x random other SS1s.
Previous: SE5, 3 x SE5a, 2 x SE6a, 3 x SE6b, GTC, 2.9i GTC, 3 x 1600 SS1, 1300 SS1, Mk1 Ti Sabre, Mk1.5 CVH Sabre
Chief mechanic for: 1400 K series SS1 (Megan3), 1400 CVH EFi SS1 (Grawpy), 1300 SS1 (Number One) & Sarah's coupe.

Post Reply

Return to “SS1/SST/Sabre”