Higher profile tires will help if you have low profile tires. Im trying to get a 5 speed without breaking the budget. So while im waiting i went for the 3.7 ratio diff center from a bluebird and it works a treat. i did ring 50 wreckers and found one in Taree for $150 earlier this year. The others i seen were in Tamworth when i was there for work but they are all in a pile and have to sort through them to identify. the guy doesn't know what they are off and doesn't care. There would be 120y, 1200 ute and sedan diffs maybe stanza/bluebird in original housings.

I seen a rusty pile of datsun diffs in the weather and got confused looking so i left. I will say but when i do get the 5 speed ill go back to 4.11