4.11 are standard on all 1ks but the ute had the 4.44 so dont worry about finding one. Unless you cant find a 1200 diff or early pre 74 120y centre. Most 1k diffs have a bit of slack in them by now so most are a bit noisy. Best use a cut down pintara, late commercial van or other diff from live axle ute etc. However weight is the problem if its a race car. Im using an Alfa 105 gt diff which is lsd, all alloy and can handle the torque of a small block. Its best to use a diff from a sports car with live axle which has the lsd option centre from well known 3rd party companies. eg Mg.

How did you do that?

what kind of diffs are we talking here, any suggestions i was going to go for a KE30 corrola diff for my 120Y coupe race car but if you have a better lighter LSD internal option then tell me please...