You do know these are 660cc three cylinder don't you? That nomally puts people off.
I've built two, one with a Cappuccino motor, DOHC, 12 Valve (search for "Greg" as the author in the suzuki page - his car has been discussed at length, but we built it a few years ago) and one SOHC 8 valve in my 1.0 litre, which has been running for a bit over 12 months.
Fitting them isn't that hard - engine mounts line up with 1.0 litre mounts, gearbox is 1.0 size, jackshaft is as per a 1.0. gearbox mount needs modification. wiring is no biggy. exhaust is on the same side, airbox, radiator etc is all easy (unless you go to a K6A) Clutches are a bit of a hassle- they are very close to a F8 carry clutch but not quite - the cover is different and is unique to the Jimny 660. These can be refirbished though.
I'm starting another with a K6A - all alloy, knock sensor etc - much more advanced motor.
They are great motors - wider rev range than the G series, EFI, light weight, better gearbox gearing (if you use the sierra gearbox, not the cappuccino box) They're reliable. Parts are available ex sydney but also from a range of OS suppliers, including the US. They leave lots of room in the engine bay. My car is pretty heavy and runs 34" tyres and I can sit at 100kph pretty comfortably, even when packed for a camping trip. I run Trail tough 6.5:1 transfer gears and 5.12 diffs - I spin about 4K @ 100km/h on the highway. My max revs are 6500 as I have the "commercial" motor from a 1990 sierra, but it pulls them strong and clean. K6A's are 8500 rpm limited and cappucino motors are 9200 rpm limited.
The two F6A motors I've worked with both go slightly better than a healthy 1.3 in untuned form. I expect the K will be much better - they have much more torque.
However, getting one in isn't easy at all. The Cap motor came from a front cut ex adelaide. Cap cuts are worth pretty big $$ - $2200 upwards.
Mine came from a cut that came into country victoria and was $1200, but I don't think these guys are dealing with them anymore.
Cj can tell as much of the stoy as he wants, but he spent about 6 months searching for one and eventually got a price from an export company in Japan for a late model K6A from a coil sierra, in a front cut. It was about $8500 landed.
There are a few FWD motors around from suzuki alto hatchbacks. These are much easier to get but they're more money as the mighty boy/ alto hatch guys like these motors. They're less useful for us as they have different manifolding, sump, starter, water piping etc. If you set up a jimny (sierra) motor and have all the trim, the FWD motors can be a good source of motor cores though.
I would say importing one from Japan isn't worth it.
Now, there is a catch. If you want the car to be legal, you'll need an understanding engineer and most likely you'll need to start with a commercial plated 1.0 litre. (Not a maruti) There is no ADR emissions complicance information on the 660 motors so for cars covered by later emissions ADR's (like all 1.3's and anything after ULP came in) you will have major difficulty engineering one. If you start with 1.0 with a commercial plate, basically, very minimal emissions ADRs apply and the 660 will only have to pass a CO test and noise- easily passed.
Commerical plated sierras include 1.0 traybacks and 1.0 2 seat hardtops with 16" wheels. Basically, if it had front drums and 16" wheels, it will have a commercial complicance plate.
There's heaps more tech I have on these motors and the conversion if you decide to go that way.
Steve.