My nephew parted a couple of rusty 80's era spiders last summer. I bought one of the diffs from him. Mostly, I bought it for extra LSD discs. Upon taking it apart this morning, I was very surprised to find 10 teeth on the pinion and 43 on the ring gear! Everything else about the diff is normal. From reading this thread, I can only assume the car was special ordered with the 4.30? Or perhaps a previous owner found a Euro Berlina diff to put in it.
I put a 4.10 in my street GTV (currently in pieces), but I like the idea of the 4.30 even beter!
'66 GTV racecar, '71 Spider racecar, '74 GTV street car, '71 GTV project