WillG80 Reader
7/30/21 2:42 p.m.

About a month ago I stumbled across a 1974 XJ6 during some unnecessary marketplace scrolling. A few minutes later and I had the seller talked down to $200 so I proceeded to grab the trailer and off I went. Several hours later and this was in my yard. 

The good: It was only $200. It came with a clean title. 
The bad: It was only $200. There's no engine. The interior is rough. Wiring seems to be a mess. 
The ugly: It was only $200. The driver side floorboard seems to have dissolved over time, along with a few other parts. 

The plan: Spend as little as possible to get it ready for the Rambler 500 in Colorado on Sept 17-19. American V8 power of some sort.




Wally (Forum Supporter)
Wally (Forum Supporter) MegaDork
7/30/21 2:47 p.m.

I see nothing wrong with this plan 

WillG80 Reader
7/30/21 2:49 p.m.

Fast forward a week of frantically searching for an engine/trans and I stumbled across this mobile meth lab in Grand Junction. Off I went again on another adventure.

Edit: $400 with me pulling it. 


Some cutting required. 


And a little help from the Powerstroke



and finally...


All said and done I was there for less than 5 hours, so I'm happy. Minimal cussing, cuts and bruises. 


After a good bath today






WillG80 Reader
7/30/21 2:55 p.m.

From the engine block code I've been able to gather that I have a 440 big block produced between late 1975-1979. The casting number is 4006630, followed by 440-3. Some research later and I know I have a 727 Torqueflite transmission. This is the first Mopar I've ever owned other than a diesel truck so it's all new to me. 

I grabbed as much of the engine wiring harness as I was able to, but I cut off the ends going to the cab. Does anybody have a diagram for this thing or know where I can get one? I have no idea how to even get it running. I'm assuming most of the wires are for the temp sensors etc.? Since it's carb'd?

Robbie (Forum Supporter)
Robbie (Forum Supporter) MegaDork
7/30/21 3:03 p.m.

oh my, AWESOME!!

Im guessing wires would mostly be for dash sensors (temp, like you say but also, RPM, maybe oil pressure, etc). There is probably a wire to the choke - I bet it is 'electric choke'. Is the ignition controlled by some sort of module? That Niehoff thing? someone else will know significantly more. 

Robbie (Forum Supporter)
Robbie (Forum Supporter) MegaDork
7/30/21 3:05 p.m.

You'll also have starter and alternator (and maybe the voltage regulator is separate) but those wires should be easy to identify based on their termination locations.

frenchyd UltimaDork
7/30/21 3:19 p.m.

In reply to WillG80 :

OK that probably will weigh about what the 6 did. But here's the bad news,  

   Yep!  Wiring.  The major problem with every Jaguar.  Either accept unreliability or replace all the wires. Find an 8 cylinder tachometer. 
  All the bolts Are American sizes. Leave yours metric at home. 
  The rotors are probably solid disk.  It's OK the vented rotors from the XJ12/S will fit and you can either use rebuilt calipers from a XJ12  ( Try Rock Auto ) or buy from  Wilwood. 
    The rear end will easily handle the power but grease it.  There are less than 200 fittings back there.  Make sure you get them all.  If the fitting won't take grease try replacing the fitting ( American sizes)  Especially the rear hubs.  On top of each of the rear hub carrier is a domed access plug. Pop it off and fill each hub carrier with grease. 
    Lift the back off the ground ( Jack in the center with a wood block on your Jack )  with both rear wheels off the ground give one wheel a turn by hand. If the other one turns the same direction you have a positraction unit. In addition to 90 weight gear lube you have to have  the positraction supplement or you will burn out the positraction.  If the other wheel turns backwards it's an open rear end and doesn't require the supplement. 
  Brake work on the rear end is best done by removing the rear end.  Once you figure out how to it's about an hour job. Do not attempt to work on the rear brakes under the car.   What will be done quickly out from under the car will take forever and chew up your hands if you don't listen to me.  
       The stock radiator is very good. Just make sure the seals around the edge are in place.  
       This car will be heavy. 4300 pounds. 
 At least 1300 pounds is heavy luxury stuff.  One of the heaviest pieces is the HVAC unit. Behind the dash. 
     The wheels are Chevy (Vette  or Camaro)  bolt pattern  just because they bolt on doesn't mean they won't rub though so check them out. 
      Rust.  The floor boards just put a piece of tin over the worst area. Pop rivets to hold it in place. 
   However the drag links in the rear end are bolted to the bottom of the floor boards.   You don't want those pulling loose.  Put the "tin" on the floor boards in the back seat then go underneath and you'll see the drag links bolted to the floor. There are 4 rivets holding that plate on.  chisel the rivet heads off and then drill through up into  another plate of steel 3/8ths minimum of 6"x6"  on top of the "tin"  Using 3/8ths bolts squeeze the whole assembly together.  

(1/8th inch thick ) 

Dusterbd13-michael MegaDork
7/30/21 3:20 p.m.

Look up the mopar performance wiring directions for electronic ignition conversions. That will give you all the information you need for ballast resistor, coil, amd box wiring.

Starter will be (most likely) like a ford, with external solenoid. At least they were on that era small blocks.

Alternator is a piece of E36 M3. Mopar alternators weren't worth their weight is diarrhea. Go with a gm. Should be an almost direct swap, and easy one wire wiring. 

Tom1200 SuperDork
7/30/21 3:35 p.m.

You're on the GRM Forum asking how crazy or stupid you are..................the fact that you're here pretty much says you have reached the Nirvana of stupid crazy.

Proceed with due haste.

AnthonyGS (Forum Supporter)
AnthonyGS (Forum Supporter) SuperDork
7/30/21 3:42 p.m.

You are crazy, but I like it!  Please go on!

Pushrod Reader
7/30/21 3:47 p.m.

In reply to WillG80 :

In spite of your laudatory cleaning efforts, I can still see Walter White & Jesse Pinkman staggering out of the door clutching their facemasks.... :)

MadScientistMatt UltimaDork
7/30/21 4:14 p.m.

Looks like it's got more engine compartment room than my Dodge Dart, and people have put big blocks in those...

WillG80 Reader
7/30/21 4:56 p.m.
Pushrod said:

In reply to WillG80 :

In spite of your laudatory cleaning efforts, I can still see Walter White & Jesse Pinkman staggering out of the door clutching their facemasks.... :)

Yup, the RV had Pinkman written all over it. Found these interesting items inside...

WillG80 Reader
8/5/21 1:51 p.m.

Got a Nissan Maxima radiator and electric fan mounted. It's from a V6 model so hopefully it's enough to keep it cool. I figured I'll run the fans on a manual switch and keep them on anytime the engine is running. 

Here's where I'm lost... does anybody know how to wire the fans to be on max speed all the time with a single switch and relay? Here's a wiring diagram for the Maxima that I found. Can I take a single relay and have wires go to both fans? Does the positive need to go to multiple wires on each fan since there are 4 wires per fan? 


Robbie (Forum Supporter)
Robbie (Forum Supporter) MegaDork
8/5/21 2:07 p.m.

I think to decipher that we need to know if the 3 relays are normally closed, normally open, or, one of each (like most automotive relays - but then you need to know which is NO and NC in the diagram).

But to me the fans look like they have 2 hots and 2 possible grounds. I'd resistance test one to see if they work in pairs (one hot and one ground for low speed, and the other pair for high speed). If they do work in pairs, then it is easy.

WillG80 Reader
8/5/21 2:27 p.m.

In reply to Robbie (Forum Supporter) :

Thanks Robbie. I Ohm tested all 6 possible wire combinations for one of the fans, and always got a resistance between 1.4-1.9 ohms. Does that mean they are all connected somehow? 

frenchyd UltimaDork
8/5/21 2:54 p.m.

In reply to WillG80 :

I doubt it will keep it cool unless a Nissan V6 throws out more heat than a Jaguar 4.2 in line six does. 
The stock radiator is a very thick core with some real tricks to make it suck every degree possible out of the water. 
  Most radiators take hot water in at the top on one side and you suck cooler water out the bottom on the opposite side.  The Jaguar's radiator forces the water to flow 3 different ways before arriving  at the outlet. With each change of direction more heat is extracted. 
  The reason this is critical is because of the relatively tight engine compartment which is poor at letting air flow through it. 
 While a 90 degree V8 blocks more air than an in line 6 or a 60 degree V12  Without the luxury junk like A/C  etc. you'll get more air through than Jaguar's do stock. 

frenchyd UltimaDork
8/5/21 3:19 p.m.

Suspension tricks.  The front coils are bigger than most American coils. Race cars like stiff suspension. And well the Jaguar is Soft, part of the luxury ride.  So start cutting off one coil ( per side) at a time. Each coil you cut off will stiffen the car up as well as lower it to give you a lower center of gravity. 
     The front sub frame is mounted on rubber bushings. By now they are shot. You can either remove them completely and bolt everything solidly together, but that will lower the car further.  Or replace them with aluminum blocks with a hole drilled through them.  
   The steering rack is mounted with rubber bushings that by now make steering unbelievably sloppy.  The easy way is to buy nylon bushings. Rob Beere in England sells them as do others probably cheaper. Or if like me too cheap,  make your own bushings. That will tighten up the steering a lot!!   
 Finally that big steering wheel can be replaced with a smaller one. It will give you faster steering and it's still plenty easy to steer.  
     Sway bars. Stock is fine. If you really want a stiffer one the V12 sedans had the biggest ones until about the mid 80's.  Same with rear sway bar.  But a lot of racers don't use a rear bar at all . They feel it introduces too much under steer  ( or in stock car parlance  push ). 
 Don't forget the XJS is the same chassis so parts are interchangeable. 

Robbie (Forum Supporter)
Robbie (Forum Supporter) MegaDork
8/5/21 3:29 p.m.
WillG80 said:

In reply to Robbie (Forum Supporter) :

Thanks Robbie. I Ohm tested all 6 possible wire combinations for one of the fans, and always got a resistance between 1.4-1.9 ohms. Does that mean they are all connected somehow? 

At the very least, your diagram shows motor 1 ALWAYS has 12v going to pin 1 and 2, and motor 2 ALWAYS has pin 3 and 4 grounded. It looks like when motor relay 1 comes on, that grounds motor 1 pin 3. So I'd try to hook up a motor like that and see if you get slow or fast. Then I'd try grounding pin 4, and then maybe ground both at the same time. 

WillG80 Reader
8/5/21 4:51 p.m.

In reply to frenchyd :

Thanks frenchyd, I appreciate all your knowledge on the Jags. I'm sure I'll have some specific questions for you at some point. This car probably won't really get modified (yet), unless things break. It's meant to be a fun beater. Besides the rambler 500 and maybe one Rallycross a year, I'll drive it around the mountains when I take the dog for a walk etc. The front shocks were missing so I ordered the cheapest set I could find to get it back on the road. The rest of the suspension will stay put for now. The car is way too rough to try to save long term. 

I figured cooling will be a challenge, that's why I want the fans on all the time. If this doesn't work I'll start looking into aftermarket aluminum radiators. Luckily there is no hood so airflow won't be constructed by the small engine bay. 

WillG80 Reader
8/23/21 9:33 p.m.

A quick update on the progress. Old engine mounts out.


New mounts


And she's in

Old starter was hitting the steering shaft so it was replaced with a high torque mini starter. It was huge!! Luckily it looks like all the Chrysler V8s used the same starter so it was easy to find and pretty inexpensive. 



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