A member here has done this swap. But from what he tells me, it definately is not a plug n play. It required the complete VS wiring to be put into the VN.

no doubt he will reply here when he reads this.

but it would be far simpler to sell the VS and go buy a new motor for the VN.

you can probably find any number of vn with perfectly good motors laying around where ever you are. i live in a rural area and know of at least 3 just sitting in backyards.

Here is what i wrote when I did it:

VN to VS ecotec conversion

With the drive line in my current VN Commodore wagon showing the signs of age, the torque converter needing replacement and the engine having 350000km on the clock plus massive tow bar fitted by a previous owner, With this in mind I decided to do an engine and transmission exchange.

I rang the local wreckers for prices and kept a lookout in the papers and auctions for a damaged low mileage VN. I also consulted as many people as possible who had in depth Commodore knowledge.

From this I found I could also use a VP engine transmission combo with the addition of the VP computer chip or with some minor wiring changes I could also use a VR engine and transmission. This allowed me to look wider and planned to do the conversion over the Easter break as it is my only car.

Two weeks before Easter a friend knocked on the door about a VS Commodore sedan that had a rear hit. Knowing they have the ecotech engine I made a couple of phone calls and found that the change was a very complicated one, but as I had the whole car I could convert the car to a VS.

The next week was spent planning what parts were going to be converted over. Knowing the wiring was radically different the entire harness from dash forward was to be used. From this the dash and steering was also going to be converted. This would also give tilt and reach steering.

The plan was:

Remove engine and interior from the VS
Remove engine and interior from the VN
Change steering column and rack from VS to VN
Remove both wiring harnesses and install VS into VN
Install motor and transmission
Install VS dash and central locking into VN.

With all the plans in place I started midway through the Friday and had the engine and gearbox out by Friday evening. Then pushing the VS out to start the conversion on the Saturday.

Starting early on Saturday morning I had the old engine and interior out by midday. This is when it started getting interesting, with both engine bays and interiors empty I started on the steering conversion, however, I was soon to find that the opening in the firewall was too large to fit the VS column without removing a section of the VS firewall and installing into the VN. I then decided that I would use the old VN column and steering. The VS dash board was put in place to see if the VN column would be OK with this and there were no real hick ups. Of some note was that the accelerator pedal needed to be changed also, as the VS has a larger fastener on the end of the cable.

So now I moved to changing the wiring so that the engine could be placed back in. This meant pulling all the engine bay wiring through the fire wall and removing the ignition switch from the column. As I had a full metal jacket on the VN this meant taking the column out. By the end of the day I had removed both harnesses and placed the VS harness into the VN.

Sunday being Easter meant a late start to the day but by the end of the day I placed the engine in and had started to connect the harness. Unfortunately I found my first real hurdle, the exhaust was radically different in the VS and as I had a wagon and the donor car was a sedan I would have to source an exhaust on Monday. Being a public holiday was the problem though. This was to keep the car from being finished as I did not find one until Tuesday.

With the engine in place all that had to be done now was to fit the VS dash. This started out relatively easily, with much of the dash in place within an hour, however it was at this point that another drama was to unfold. When I first fitted the dash the VS has the demist as part of the car and the VN as part of the dash. Looking at the dash I figured that enough air would get from under the dash to the screen for Queensland winters, but when I went to install the instrument surround it became obvious that the AC outlet was not going to align with the centre outlet. Looking at the other AC unit it would be too difficult in the time available to modify my AC unit for the VS so the VS dash was removed and the VN dash reinstalled.

As I had now lost a lot of time I temporarily mounted the VS central switches above the radio to be incorporated in VN switches at a latter stage. The central locking and power mirrors in the VS are also different and these were changed to the VS the following weekend (about 2 hours to complete). A small adaptor was also made to connect the front VS wiring to the VN rear wiring, had the donor car been a wagon it would be easier to replace the rear wiring. The light switch had to mounted on the right side and the headlights themselves had to be rewired internally.

If you are going to make this adaptor for the rear wiring, ensure you identify all wires heading to the rear before you starts the job, the connector is located behind the driver's kick panel. There are two connectors, one for the rear lighting and the other for the fuel pump. The interior light is the same in both VN and VS.

By late afternoon I fired up the engine to make sure everything was fine and put away the tools for the weekend.

Some of the other minor items were the VS wipers had to be used, but to change these is 3 screws and the motor and arms come out as one. (I wish I had known about these when I helped modified an FC a few years ago). Washer motor is also moved from the rear right of the engine compartment to front left and air conditioning high and low pressure switches have to be rewired.

It took 30 minutes to fit the exhaust and then test drive the car. The overall result was now the car has a slight power increase, has lost the characteristic VN rattle, has no vibration from the transmission and uses about 10% less fuel. For a total outlay of 4 days work and about $700 the wife is happy with the result.

There are some nice features of the VS that have also come across, two stage remote control central locking, delay off interior light, headlamps auto off, built in immobiliser, electronic controlled transmission with power button, column mounted wiper switch.

If I had to do the same again I think I could get it down to 2.5 days, or now that I know the short comings, be able to fit the steering and dash in the 4 days. But I will get the chance as the old engine is being used as a template to possibly fit a V6 to an FC Holden. We shall probably use a VN/VS dash, steering and air conditioning.

Special thanks must go to "commodore nut" who helped with many questions over the week leading to and during the conversion, Park Ridge auto recyclers for the amount of time I spent crawling over their cars checking everything twice and finding those parts that needed to be replaced.

If you wish to do the conversion here are some of the pitfalls and choices you have:

Donor car to be the same as your car, if not you will need wiring adaptor for front to rear and the exhaust from catalytic converter back (manifold to cat same in sedan and wagon).
If you want VS dash pad then integrate VN demister into the VS dash pad and graft VS AC outlet into VN outlet. (the VS and VN firewall shape apparently stops the VS AC unit from being bolted into the VN) You shall also require all the under dash frame from the VS and AC ducts and fitment of AC outlets to your door trims or fit VS trims.
The VS speaker pods can be fitted to the VN doors and the door wiring has the speaker wiring. If using VN door trims simply cut out around speaker area and fit VS map pocket. You may give some consideration to fitting VS door trims and seats.
If using the VN dash you will need to move/rewire the switches for hazards, air conditioner, heated rear window and lights. You can also use VP dash switches as they have hazard and heated rear window on the left.
If you want the VS steering column you will have to graft in the VS column bottom support into your VN firewall and change the rack.
If you want to use the VS column cover you will need to use a VS steering wheel and fuse panel cover, alternatively cut a hole in the VN column cover for the wiper switch on the left, the VN holder on the steering column has provision for LH switch.
To move the washer bottle you will need a 50mm hole saw plus the VS vacuum canister and bracket, or unpick the wiring to the VS bottle and leave the VN washer bottle.
If you do not de-gas the air conditioner you will need to wire the high and low pressure switches from the 4 terminal VS connector near the horn and bridge out the fan switch. This will keep the fan on all the time. The VN compressor will also only bolt up with three bolts, as the front top mount is different on the ecotec engine. If you do de-gas the systems then you can use the VS air conditioning system and lines etc. The under dash unit is apparently different though
You can put the fender mounted indicators by cutting a couple of holes in the front inner and outer guards.
Alternatively you can fit the VS guards, bonnet, lights and bumpers to convert you car externally to a VS. If you use VN front you will have to rewire the headlights internally.
The VS bonnet struts are easily fitted to a VN bonnet.
The power button can be left in the bottom of the centre console if you want to use the VN console top.
Wagon owners using sedan donor can fit VS rear switch (part of the front wiper switch) or leave the VN switches and wire them in. Central locking also goes to tailgate if fitting wagon rear harness.
VN and VS gearbox cross members and mounts are different but either can be used. I found the VS easier to install and it has 4 bolts to the body and the VN only 2.
When removing the engine simply undo the engine mounts under the cross member, but when reinstalling place the mounts into the cross member. The LH mount will have to have the VS bracket attached so the AC compressor must be off the engine. There is enough room to place the compressor back on with the engine in place.

Many people have expressed caution about removing wiring from a vehicle, remember that the harness is designed to be installed on a production line without error. To do this GM Holden have designed the connectors to be unique in areas where you have more than one connection to ensure no mix ups. The same occurs with accessories. To disconnect the engine electrically remove both positive and negative terminals on the battery, unplug the computer behind the LH kick panel and cross dash connector and pull harness through firewall. Unplug connectors near brake booster and disconnect engine bay wiring harness at main fuses and earth connection on inner guard

To remove the engine bay wiring, unplug headlights, horn, washer motor air conditioning high and low pressure switches, remove relays and unclip relay bases and fuse holder. Pull harness into cabin through firewall. You will need to be patient with relay bases as the harness is very tight coming through (as I was not using the VN harness again I cut the relay bases off rather than much around). Unplug rear harness, interior light, ignition switch, blinkers and door harnesses. To remove the rest of the harness you will need to remove the dash on a VN but on a VS it unplugs. Unscrew fuse holder and remove. When disconnected the instrument wiring make sure to not the position of the three connectors and their orientation.

When you lay it out on the ground you will see what goes where simply by its location. When reinstalling the only real problem can arise with the relays. Some relays have 4 terminals and others have 5. If you fit a 4 terminal relay to a 5 terminal base you might disconnect a function completely unrelated. A friend recently purchased a VN which had a separate switch for the engine fan and the air conditioner would not work. I traced it to the 5 terminal lamp check relay being replaced by a 4 terminal relay. When replacing relays check that each wire in the holder aligns with a terminal on the relay. If in doubt replace all relays with 5 terminal relays

If considering the conversion you will need the following items from the VS no matter what options you choose:

Ecotec engine and accessories, manifolds, LH mount bracket, air intake and filter housing top. (You can drill a 20mm hole in your top to fit the air sensor)
Instrument assembly (although they look the same the wiring is different)
Ignition lock ring with remote keys
Both computers
Complete front wiring harness, including engine, engine compartment, dash and doors
Accelerator pedal and cable
Central locking, power mirrors and windows all go into the VN doors, but if you have power mirrors the connector is different in VS. The mirror switches on VN and VS are interchangeable, but their size is different. The central locking motors are also different and you will need to fit the VS units.
Exhaust system.
Radiator, overflow and 2 speed fan.
Power steering pump, lines and reservoir.
Carbon canister and vent pipe.
Wiper motor and switch.
Heater hot water valve and mount.

If the donor car has ABS this will not be able to be transferred over as the sensors in the hubs are different than the VP type and VS hubs will not fit the VN/VP.
The air bags should not be transferred over as these are calibrated to the weight and crumple zones of the car and could go off at the wrong time. Just remove the fuses for ABS and or air bag will disable these systems.

For VR owners looking at converting then there shall be less problems with the interior, but you will still require the above from the VS with the exception of the wiper motor, instruments and instrument wiring

I have since fitted a VS Statesman dash to the car.

Thanks very much to everyone for the replies and suggestions, especially Warren, after reading Warrens reply I carefully considered my options for about one millisec and have opted to find a reasonably good VN motor and go that way. Again thanks to all, Bambino

Hi, im looking to do the same, putting a vs into a vn, however id like to know if i could use the vn transmission instead of the later one. my reasoning is that im putting in in a VN ute and its column change, ive been told that the linkages wont match up with the newer trans? also ill have no place for the power button. any help would be awesome!