yeah agreed, I initially thought I would be ok with the rear really soft and started out that way racing, but the amount of body roll in the rear is becoming problematic. If I need to balance it after I install a rear ARB, I can make front changes to rebalance or re-assess.
There is nothing crazy about the setup, more following others who have been down this path. Their decisions support my calculations, which is always nice.

It is fun to drive, I know there is more in her with a better setup (Rear end has too much roll).
Fix on the way....
Car makes around 300rwhp, remember it has a 36mm restrictor - (I know the exact figure but that's a good enough estimate )

Developing a simply CA head drain, using the rear welsh plug to tap in a 7/8" UNF (-10 AN thread) thread into the welsh plug for a oil return, push back in, seal with a ORB to AN fitting and weld on a AN fitting to the sump, simple (rear welsh plugs are 25mm if anyone is interested, pretty common). You could tap a 1-1/16" UNF directly into the head which would be a -12 AN thread fitting, but I didn't want to modify the head without trying the welsh plug idea first (plus I have a 7/8" UNF tap but not a 1-1/16" UNF)

test session footage
Barbagallo Test session

Took the car out for a practice at Barbagallo on Saturday.
Best completed lap was a 1:05.6s. Funny thing was two laps later the session ended, I caught the red light after the last turn and pulled straight into pit lane. Back in the pits I reviewed the log and realised that lap was 0.8sec up on my previous best so was heading down main straight for a 1:04.8s which isn't too bad considering it was my first time at the track. Lap record for IP is a 1:02.??.

It was a really hot day and the car spat coolant in all three sessions. I thought it was overheating but reviewing the log have come to the conclusion that I have a blown headgasket. The coolant pressure was going up but the temp was in the 80s Deg. I have had issues with bubbles in the coolent before.
End result I have pulled the engine out and will replace it before the race session begins. Going to do some other prevantative maintence whilst the engine is out (Clutch, check gearbox, baffled sump install and head oil drain).

Looking to install a rear ARB before the first race, not happy with the amount of body roll in the car. Front ARB should be ok, but rears springs are very soft (Which is good for ride but not roll), I have a baseline now. It will be interesting to the lap times with each change.

I have some in car footage of the practice that i'll upload when I get it all together. Added a rear facing camera so now need some software to stitch it all together.

Ok for my opinion,
G-series (Hilux), its what I run in my 1200 Race car.
If you are never going to see the road, look to run floater hubs. This is safer for drag/circuit racing and much easier to do as an alternative to shortening. This prevents the wheel coming off when you snap an axle. Can also camber the rear.
http://msfracingcomponents.com.au/fullfloatinghubkits/ is a good start.
If you are drag racing then the standard Toyota LSD should be fine. Bolt in upgrade is a Cusco. Kaaz requires a ring gear spacer to fit. cheaper options (non ramped) are Loka's which would work well for drag racing. or for a cheap option Spool (full, mini, GIC).
Remember when you replace the rear suspension or convert to 4 link, consider how the thing will roll and act under acceleration, braking (anti's - Dive/Squat), there is an art to getting up the rear properly and not just weld 4 equal length rods in and call it a 4 link.

Hope that helps, good luck

Bryan

ddgonzal,
Not sure why Hilux (Toyota G-series) has the wrong stud pattern? aren't 2WD hilux 5x114.3? and 4WD 6x???. BW78 is either 4x114.3 (R31) and other 5x??? axles.

As for decision:
Either way you go the machining work is about the same and nullifies that as a discriminating factor. Although.... It is possible to machine just one BW78 axle to shorten for a 1200. But given you are tubbing with presumably big offset wheels, you will need to shorten both sides.

Everyone can pick up either BW78 (Falcon, Commodore Nissan R31) or a Toyota G series (Land cruiser Prado, Hilux, Hiace, 4 runner etc) for next to nothing, neither come with the right spring perch offset or 4 Link bar offset.
Look at the axle strength option, G series has bigger, thicker axles standard (30 v 28 spline).
The G series is an 8" ring gear, I think BW78 is 7.8" (I think). Not going to worry you.
G series would probably be heavier overall.
Ratios will be important for your application. If you need taller then 3.5:1, you will struggle to get with a G series setup (Very hard to find). short gears are the opposite, harder to get in the BW78, heaps in the G series due to the 4WD range it was brought out in.
LSDs- Stock both are very crap for anything other then mild street and drag racing, on a circuit track both standard diff will not cut the mustard on a mild track worthy car. BW78 has a cone style LSD (Happy to be corrected on this) where as the G series has preloaded clutch plates.
If you go aftermarket LSDs, options available for both. Cusco/Kaaz, Torson, Lokers, Spools etc.
Ratio changes are arguably easier with a G series as the third member is removable, where as the BW78 are attached to the housing. Although the majority of people would not change ratios very often.

Whilst I have a preference for my application, I have tried to keep my bias out of the above detail, it is really up to you both have their advantages.
There are other options too, early Mazda's (with the right aftermarket upgrades can be good), ford 9" or 8" cheaper replacement parts, arguably overkill.

Yes they have differnt purposes.
BOV releases the built up pressure between the compressor outlet and the throttle body (Butterfly). Works when throttle is closed to release this pressure.

Wastegate controls the exhaust gas flow through the turbine. Used to limit the turbo shaft speed which in turn limits compressor output mass flow.

Hahaha, what he said above

I had a similar bad experience with Scottsoldautorubber, very rude on the phone.
I ended up using New Old Car Company/Mazda Phils in QLD.
We were up there on holidays and dropped into the warehouse to pick up the bits.

Cheers

Bryan

Unfortunately the answer will be depends.
Depends on your current brake performance and if your chosen engineer for the engine conversion agrees the brakes have the required performance. The engineer should consider the system performance and not how big/modified the brakes are. So it it meets the required performance, you should be ok.
It is however sage advice to consider increasing brake performance, you don't need to go over the top here though. Refresh the system, put in some decent pads and test it, just as important is the rest of the suspension, check shocks and suspension bushes too. Its not wasted money.

Good luck.

Bryan

This thread is pretty funny. I have the same issue with my coupe. Drivers side is out by about 10mm. I have replaced my diff with a hilux which obviously is wider. I was pretty accurate measuring to ensure the mounts were centred still ended up with it off. I wonder if the chassis rails are not symetrical on the body?? Datsun were not renound for being a top of the range car back in the day so anything is possible i guess.