Well. I first want to start by saying how very lucky I feel to have found this forum and thank-you. My project truck is a 66' regular cab SWB. I purchased a rusted 73' LWB XLT to give up it's PDB/PS among a list of other things for use on my 66'. I would like to do a complete drivetrain swap also. My question is the rear upper shock attachment point on the 66 uses a side connection thru-bolt/nut. In contrast the 73' uses an end stud/nut connection, similar to the front shock orientation on my 66'. Also which rear springs will be used? My 66' used 6 leaves and the eye mounts are 50" on center and the 73' has 5 leaves with mounts 55 1/2" on center? Any help would be very appreciated.
Thanks
Cheers!

from an I6-240, manual 4spd granny, unknown rear
to a (360/390 still unsure) 3spd auto, 9"

 

Welcome to FTE

I don't see the reason why you would want to replace the 1965/67 rear springs with 1973/79 rear springs.

In order to do this, you would have to change the front & rear hanger brackets, rear shackle brackets, rear shock absorber brackets, because...

1965/67 F100 2WD's have 2 1/4" wide rear springs that are 24" > eye bolt < 28."

1973/79 F100, 1975/79 F150 2WD rear springs are 2 1/2" wide that are 24" > eyebolt < 31 1/2."

And, besides the rear springs being wider and longer, the rear axle is also wider 1973/79 vs 1965/67.

The width between the inner frame rails behind the cab prior to 1973 is 33 1/2."

1973/79 F100, 1975/79 F150 width between the inner frame rails behind the cab is 37 1/2."

 

Sorry ND. Maybe I was unclear, the 66' is the keeper and the 73' is the donor. Do you see this as a bolt in swap out. Even with the different spring dimensions. I don't want to change any of the springs and was hoping i could just hang the 9" rear from the 73' donor onto my 66' frame. What about the rear shock differences I mentioned earlier. I guess what I really need to define is where am I going to draw the line between the 2

 

Why are you wanting to swap rear ends? Is there a problem with your current one? If not, leave it in place. I guess I'm unclear as to what your wanting to swap out and why. You mentioned a complete drivetrain swap but not the reasons why. Sounds like your making a LOT of extra work for not much if any gain.

 

Let me see if I can clarify what you're saying - or you can correct what I misunderstand. Your keeper project truck is a '66 SWB, Standard Cab and currently has the 240 CI I-6 with a 4 speed and unknown rear end. You bought a donor '73 LWB XLT from which you intend to harvest its FE V8 engine, automatic transmission, power disc brakes, power steering, (probably the steering column and transmission linkage), and to put them into the '66. You would also like to harvest the rear suspension and rear end and want to know if this is a "bolt in". Number Dummy has stated that the rear suspension swap is NOT a bolt in. So the recommendation is to stick with your '66's rear suspension. Get new shocks and bushings. Have the springs rearched, or if you don't think they're heavy duty enough, add a leaf or so. Get the data from your '66's warranty plate (driver's door) and post what it says. We'll decode it for you and that will tell us what your truck left the factory with. If someone hasn't messed with it, there's a better than even chance your truck already has a Ford 9 inch differential, although it wouldn't be limited slip. Or it could have an optional Dana WITH limited slip. Good luck with your project.

 

Gentlemen:
You know who you are. Thank-you for staying with me. This is where I should have started, with the necessary data.
66 nameplate- F10AL783393
73 nameplate-F10YCR50867
Can this 73 differential be attached to my 66 suspension?
If not what would your collaborative recommendation be?
Are the shocks going to be a big issue, or is it an easy fix?

Thanks

 

The numbers you gave so far don't give any info on the differentials that are in each truck. On the Warranty Plate it is listed under Axle, I believe. But, the VIN itself doesn't decode the axle.


There is a chance that nobody has done exactly what you are asking about, but hopefully someone can chime in that has.

.

 

I haven't researched the shocks so I cannot comment on them, but to put the 73 diff into the 66 the spring perches would have to be relocated.

 

Sorry I should have known about the codes. The 66 has got just the one code for both
Trans/Axel - C5
Based on condition thru-out teardown I would say the truck has been un-molested.
Virtually rust free from stem to stern. If no one objects to putting the FE and automatic in front of this differential, then thats what I'll do.

 

There is a separate TRANS code and separate AXLE code stamped on the 2nd line of the Warranty Plate. The TRANS code is listed before the AXLE code.

The TRANS code is composed of 1 letter. The AXLE code could be 1 number/1 letter, or 2 numbers, and there may be a 3rd number related to the front axle.

Sometimes these codes were stamped away from where they are supposed to be on the Warranty Plate. Too far to the right is the usual scenario.

C5 could be the AXLE code: Dana 60.2 Rear Axle (F100) / 4.10-1 / Limited Slip / 3,300 lbs. Rear Axle Capacity. The Dana has an inspection cover, the 9" does not.

C by itself could be the TRANS code: Ford type 3.03 3 Speed Manual all Syncromesh Transmission.

4 speed TRANS codes; 1966/77 F100: A = New Process 435 4 speed / F = Warner T-18 4 speed.

Look at the plate again for the correct codes.

F10AL783393: F10 = F100 2WD / A = 240 1V I-6 / L = Michigan Truck Assembly Plant / 783393 = 1966, assembled November 1965.

F10YCR50867: F10 = F100 2WD Pickup / Y = 360 2V / C = Oakville Ontario Canada Truck Assembly Plant / R50867 = 1973.

 

ND, cleaned plate lightly with thinner and see only the following -stamped characters
WB-115
COL-M
MODEL-F100
BODY-481
TRANS-
C5
AXLE-
end of line one

MAX GVW-05000
NET HP-129 4000
LOST TO THINNER-830117
end of line two

I do have an inspection cover and on the diff casting we have C30294 as well as 44.1 Bad day, can't even help you to help me. Thanks for everything, really!

 

115" Wheelbase.

M = Wimbledon White.

F100 2WD .. 5,000 lbs. GVWR

481: 4 = Medium Beige Crush Vinyl & Medium Beige Wicker Pattern Vinyl / 81 = 81A Standard Cab.

TRANS: Blank*

C5 = Dana 60.2 Rear Axle / 4.10-1 / Limited Slip / 3,300 lbs. Rear Axle Capacity.

5,000 lbs. Gross Vehicle Weight Rating.

129 net HP @ 4,000 RPM

830117:

83 = Purchased by the US Government.

0117 = Domestic Special Order number. This has to do with the transmission, since there's no code for it.

*US Gov't specified a certain transmission that was not an RPO (Regular Production Order). The truck was then sent out after it left the assembly plant to have the transmission installed.

Domestic Special Order parts are not listed in parts catalogs, as the parts were installed after the truck left the assembly line.

If a part was required for the transmission, dealer contacts FoMoCo with 6 digit DSO (830117). FoMoCo looks up the order number (0117), then tells the dealer where the part can be found.

What US Gov't agency purchased this truck? It wasn't the military (USA/USAF/USCG/USMC/USN) or the Department of the Interior, as it was painted Wimbledon White. So which Gov't agency had white trucks?

The problem is: FoMoCo THREW AWAY all the records for these trucks decades ago, so there's no way to find out.

 

Check the rear end housing and if its got a removable inspection cover on the back then its NOT a 9" rear and is probably the Dana. Sounds like an interesting truck with the Gov. special order.

 

Hey 69supercj
My diff does have an inspection cover. My goal here is to create a mild, comfortable street truck. The original drivetrain had plenty of grunt torque but I'm really wanting an FE. What about putting the FE and 3spd auto in front of the old diff? Your thoughts.

 

The Dana 60 was used in a lot of the F series trucks with the FE engine. It should be plenty stout and the transmission in between should not really matter other than possibly driveshaft yokes or little things like that depending on what you mix and match.


All of my trucks have Dana 60 rear and two have FE and one of those is automatic. Should be completely fine. The 240/300 to FE swap is fairly common, especially in the 2WD trucks.


.