Outer Limits 4x4 Board

hi all
i have an injected holden 355 stroker in my 60 series and since its pretty much overpowered but thirsty on fuel iv been looking for some lower ratio diffs for a while and have bought a couple of 9" diffs already converted to suit 45 series cruiser both fitted with 3.7 ratio centres which should be pretty close to the ratio i need and if not i can go lower as the 9" have plenty of ratios available
i know the 45 series diffs are narrower than the 60 series but an adjustment to the mounts and a set of 1.5" wheelspacers will fix that

main problem i have is that the centres are both open centres and i wanted to chuck in some lsds or lockers but it runs the standard landcruiser 30 spline axles not 28 or 31 spline 9" ones and i have no idea what was used in the 9" to run the 30 spline axles and am hoping someone knows if its a common conversion what parts are used in the 30 spline conversion and what lsd or locker i could use

thanks for reading and hope someone can help

1. swap the side splines ..

2. I'm a TLC purist .. I never thought in pull out the rear axle and run a 9inch ( recon the 9" 3rd it's better bearing suported and pinion strenght ) most if I had the 3.70 option in TLC axles ..

3. Lower ratio .. ? never.

Simple solution = big tires