hi there, new to the site but not to Datos,i have a 67 model 4 door with an S15 SR20 VVT in it, she's been at the $$ period of doing up for years (diff,wiring, interior, paint etc) and its at the point i either get into it or get rid of it, would prefer the first tho! Q1: what is the most common diff you guys are running for these modified engines???
Q2:how do you go sourcing parts, im in need of guards as mine have been butchered and a bonnet as i had to have a TD cortina hump welded in to get over the rocker cover and the bonnet is out of shape but probably salvageable if need be Q3: and the most important of all..do you think i will be able to get the beasty rego'd with this engine, i started doing it a long time ago and the rule was 2.5 x TARE weight for naturally aspirated..
 
Thanks all hope i get some good news 

As neil said, there isnt a bolt in option available.
I have a cut down skyline diff for my sedan. Its not in properly, but as neil says it doesent leave much room, but it is probally the cheapest option as you dont have to get the wheel studs changed to keep it the 114mm 4 stud pattern.
 
In reality, since you will have to cut down anything, the cheapest available diff to you will be fine.
Really early hiluxs (77ish) with the diesel  are very skinny and are popular with plenty of early jap car modders (mazdas, corollas etc) They come in huge ratios (4.3:1) and bullet proof, but still need to be cut down.
 
Im a fan of a skyline diffs. BW stuff so common as muck,(commodore VN-VT & falcon EA - AU) plenty of rations including LSD available. 28 spline, plenty of strength.
 
Pintara diffs. 25 spline BW. smaller than the skyline stuff but still strong enough really.
 
The list is endless really. Since it all has to be cut down it doent matter.
 
As for weather you will get it licensed.
 
Look up VSB 14 and look in the engine section.
http://www.infrastructure.gov.au/roads/vehicle_regulation/bulletin/vsb_ncop.aspx

 
It has a table in there listing the maximum capacities recommended. But dont forget that it is all contextual. Its not concrete numbers...
 
As for the other mods required. Its all in VB14. Go and read that and all your questions will be answered. Its actually really clear and easy to read.
 
Oh and a very "understanding" engineer to sign off on it....
 

Iv'e got a S13 CA18 in a two door sedan.  Where i'm from that is the largest no aspro. engine I was allowed.  I thought about a 10A rotory but that was even too big.  In saying that I half way through it, like yourself, so hopefully someone will pass it.

Thanks mate
 
Times have been both interesting & busy of late but I'm not dead yet & I still have everything except the money. [LOL]
 
I now have another full race A13 with ALL the factory good stuff including Titanium rods so have a guess where that engine came from.
 
It'll be a little while before I can get back into it properly but I'm still in the game.