741 rear

After crawling under my A56 I find that the rear is a 741 3:23. I'm disappointed a little because I thought it should be a 489. From what I've read 741's came only in low performance cars. I've attached a few photos wondering if someone can tell me what the number 26 indicates. I'm not the original owner so someone may have changed it out. The car is all original up to this point. I've noticed some markings by the universal joint which may not mean anything.

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