In Vic at least, for it to pass an engineers certificate.. it would need to meet the pollution specs of whatever's newer..  so in the XB with AU engine, it needs to have all the EFI stuff on it. 
if you were cheeky enough, you could fit a CFI manifold to it, and say the XG motor is CFI spec and they may not know and you may be able to stick a carby under it depending on what you need to do rego wise?(blue slip? chat to the blue slip mob if friendly)   i don't know about simpler? from what i understand, the EA to EL wagon fuel tank fits in XB and has the EFI pump etc in it (fuel gauge will need mods, they read backwards from memory ) if you can find a pre smartlock ecu and all the wiring from EA and EB series 1 it would be pretty easy from what i've heard (even smart lock ecu with smart lock bypass isn't that hard, and even the AU ECU can be sent off somewhere and have the smart shield removed for $250 plus post each way from memory, so you could use the full VCT set up)   a lot of these "bench racing" discussions have been done in the past, but Street Machine Carnage did an AU XR6 with Barra ECU on it for turbo install, so that's also another option possibly . 

Is it possible to get a late model SOHC motor passed in NSW with a carb instead of efi in a pre july 1976 falcon?   I have two SOHC motors here in my shed, one from a 93 XG and the other from a 2002 AU XR6 VCT, and I have a ton of carby bits and pieces and even an old CFI manifold from an EA 3.9litre.   Would make an interesting engine mixing and matching bit but using a carb instead to simplify the installation in to an old pre ADR27A car.   Everyones thoughts and opinions welcome.  

Some archived info from around the net, on fitting a BA-BF wiper motor to XD-XH Falcons             Ford Falcon XD XE XF Hi all, Looking to improve the windscreen wiper performance on an XD. Has anyone been able to improve it Re-firb or re-fit Facebook.pdf

im dropping the hammer,no cole

Damn Days of thunder.....now I wanna color the rims black and turn the XB into a Nascar....🤣

Yeah good ,the street fire is perfect,after months of changing timing on my old engine, just set it conservative in the beginning at around 24 or 26 or even 20 for easy start,then lay down a rubber road.

The current spec of the 2v I have sitting in the shed is 30 thou over 250 with a Speco 214@50 thou cam, the head has been cleaned up with over sized valves. Its been Balanced as far as I aware.   I have both the factory 2V and an Aussie 4V manifold to suit the head and pacemaker headers which will go into the dual 2.5 inch system the car already has.   I'm gunna get an electric dizzy and use a Streetfire module with it.   I'm not sure what to do about the induction side so Im open to any ideas. I have thought about triples, it would be about the same cost as going efi, but would looks absolutly tits.

Absolutely.!  250 2V is a good strong engine. Seen a few with triple Webers etc, that really blew my mind. You'll have to spend a bit of cash to get the old beast into the 13's, but its very do-able. Would look killer going down the strip all blue and 12 Slotters.....

I must be getting old, sorta over V8's and the current exhaust sounds like a v8 so no point doing it just for the sound...hahaha   Gunna go 2v 250, I've got all the decals and badging to suit as well, maybe one day I'm might get hold of a clevo and drop in it.   Right now just want to get the XB's straight line performance close to my G6 (which is 228rwkw's according to Tunehouse racings dyno.). I'd be over the moon if I can get the XB to nudge a 13...

I'd keep the vinyl roof, it's just awesome as it left the factory.  If you decide later on to spice it up with a Clevo, it all just slips in.....