Guess I HAVE to take a picture, now. I have the overload, too.

 

Flex-O-Matic springs are longer, as noted in this Ford factory propaganda...

 

I was going off of numbers post he is usually right on...iwill have to measure my 71 vs my 70 flex

 

I'd like to point to what Bill said as well as how the propaganda is worded. Thank you for posting that, now I need no picture and know I have that setup as well as the overload. Also please look at how they've diagrammed the two positions; the shortening occurs when the load point of the shackle is moved up, but the spring length is always the same overall, Flex-O-Matic or not.

Edit: I feel like an ***, now. In re-reading it, the advert does say longer springs. I have my doubts.

 

If that's the case, why aren't Flex-O-Matic only springs listed in the parts catalog?

There is no listing for them, just for the compensator itself (5563).

So...according to the parts catalog...what Ford sez...is strictly propaganda.

 

I'm going try to acquire some side by side pics for comparison. Not in the parts book does not mean it doesn't exist...

 

Uh huh...That's the same old excuse I've read here more than once.

Parts catalogs were updated four times a year through their last printing.

Flex-O-Matic introduced September 1967 on 1968 F100/250's.

Last catalog printing May 1975.

That means the 1964/72 truck parts catalog was updated at least 31 times since 9/1967.

If there were errors, they would have been corrected long before.

1968/72, there are 5 different rear springs (loads rates) just for F100's. Not one is Flex-O-Matic only.

You worked in the parts dept...doncha remember the job it was to change a gazillion pages every three months?

Ford just sent out new pages, not new catalogs, as the catalog was loose leaf. It was a royal pain changing those damn pages.

1964/72 parts catalog: 6810 total pages.

 

O.k., look up an AM/FM radio for a 71/72 F100...parts book says that doesn't exist either.

 

I can't take it anymore. Photo time.

Flex-O-Matic setup in practice. I can't believe I've had this truck for almost 6 years and never once noticed this strange contraption.


Measures out 55.5" bolt to bolt. I had the other end hooked to the bolt, so take a bit off on the tape.


Now for the 78 F250, non Flex. 54.5", but when I'd measured with the bed, bumper, and tank on, I had 55.5". You take 300-400 pounds off the rear and tell me you won't have a deeper arch that results in shorter bolt to bolt measurements.


I'm pretty sure that despite a 9 year difference and weight differences, these trucks are set up so similarly, I feel it proves the point.

P.S. Bill, you said your books give you load rates, what about dimensions?
Edit: Dangitall if I didn't have to edit this once again. My apologies, Bill, you gave dimensions in post #2.

 

73 and later is different

 

There'll be no convincing you, will there? Have you taken your own photos yet? Pics or it never happened!

 

I haven't seen proof either way yet. What I have seen is a piece of Ford literature stating that the Flex-O springs are longer...

 

O.K. here you go from Eaton Detroit Spring Inc.

From their website..
"We are the only spring manufacturer to have been licensed by both Ford Motor Company and General Motors to produce Authentic Factory Replacement Springs and Parts."


Apparently they call them EZ Ride springs but they post a pic for you, complete with measurements...
EZ Ride Shackle Tech

 

regardless of what axle I put under the rear I am leaving my flex o setup I spoke to the guys at the spring shop last week and they said no problem to fabbing up some over load springs.

 

as with all things ford 3 models and 35 different parts......just look at the e-brake cable options.