How to build a v8 XF (the proper way in my opinion)
You probably have heard the story that Ford Australia never built a v8 XF Falcon. The v8 ending in the XE and returning with the EB.
As Ford had decided to not have a v8 in the engine bay, they decided they would modify the heater box, add an extra speed to the fan, change the wiring a little etc.
The biggest problem is this modifying of the heater box which meant a change to the shape of the heater box leaving it to protrude into the engine bay.
This created a problem for us that want a v8 rather than a 6 in the bay. It means the right hand side of the firewall humps out leaving not enough room for you to put in the v8, mounted on standard XD or XE v8 mounts. So, if anyone tells you a v8 drops straight in with no mods there wrong.
I have experienced this problem first hand, and I have been building an XF v8 for a number of years now. I firstly entrusted who was a local engineer to do the job for me (he is now a bankrupt) who cost me money and did a bodgy job. Firstly he "modified" the standard mounts and moved the engine forward (to get around the hump prob) leaving no room (a space the size of your key) between the front pulley bolt and the thermo I fitted. I was p**sed off and got him to fix it.
He fixed it alright, he pulled the motor out and took to the heater box firewall hump with a hammer! meaning the heater hoses were crushed and not operative.
P**sed off again i took the car back (I was thinking of legal action later) and did the job properly with the help of my fiance's father who was once a mechanic, panel beater and painter by trade.
First of all we yanked the motor out (again!, which happened to be a 302 anyway). I then acquired a rusty XD 351 v8 as a donor. I then stripped out the carpet, seats, dash and heater box of the XD & XF.
We then cut out about half of the XF firewall (the right hand side with the hump) under the lip where the firewall welds with the rest of the body but left the indent in the firewall where the fan motor of the heater box goes. We then cut the same part of the firewall out of the XD (the XD firewalls dont have the XF heater box hump) and then welded it into place on the XF.
Next the XD heater box and fitted up to the XF, for memory all but one of the holes for the bolting in of the heater box lined up. The heater box in place I put in the put back all the XF dash in place which had no trouble fitting over the XD heater box.
The box in place now, I had to get it to work. The setup for the vacuum plugs and the plug for the heater box fan was different on the XD to the XF box, not majorily so I used bits and pieces of both boxs to adapt it to the XF switches in the center console controls. The main problem seemed to be the missing fan speed, while I could get all three speeds (not four like original XF) I have to fiddle with the fan speed and the air cond controls to get them all to work. This problem could probably be fixed by an auto electrician, but I was satisfied as I didnt have the air conditioner fitted and I was trying to save some money and my fan is locked on the windscreen anyway.
The finished job once repainted looks great, looks like standard like it should. Inside there is no difference to appearance as the XD box hides neatly away behind the dash.
With the heater box and firewall problem corrected, I fitted up the v8 on standard v8 mounts (no moving the motor forward this time), with the heater hoses connected everything was working.
I not sure of the requirements in other states but the XF was now classified as modified vehicle in NSW and therefore requires an engineers report and an RTA signatory to sign off to say its road worthy (which I believe includes a working heater, to demist the windscreen).
From experience this is not a job for the light hearted, if the above sounds to much to bear consider cheating by acquiring an XD or XE shell and bolting up (some mods required) the XF panels, lights & front, rear bar (& doors, dash, seats if your keen).
I'd be happy to expand on any of the above if required. Id also like to hear from those who have already modified and built a genuine XF fitted with v8.