A more likely scenario would be czp accidentally sending you a pivot ball for a 350z gearbox rather than a 300zx box (assuming the 350z box uses the smaller thread like the later 300 boxes).
Glad you like the shift mount Sandeep (I make them) MoulaZX I have never seen the bigger thread on ANY 300 or 350Z pivot balls, They are all M10x1.5 here. You must use the shorter 350Z pivot with the cast iron fork also.
Oh cool! Heya! Yea I still can't quite explain it 100% either but thats what happened with me, and with a lot of perseverance, eventually rigged up a solution. I take then you read my posts here and the further posts in my build thread then? Regardless, happy to say that solution has now gone past 2000km (1200 miles) with no dramas at all, with quite a bit of that being traffic grid lock so a lot of constant on & off clutch. MoulaZX