I want to beef up the rear end of my 65 100. What is the best way to go about this? I haul about two Yards of bark regularly and it drags a bit don't want to break anything back there. I found an f250 would it just be a swap out leafs & rear end or am i ok with just heavier springs? Sorry it's a F100 Custom Cab W/ 352 C6 LWB.
Thanks
RCC

 

RCC, The one thing I'd be concerned about is the designed load rating of the 9" rear axle bearing. They are a one piece roller bearing design, wheras the 3/4 tons used a true cup and cone roller bearing which is larger and can handle the increased load and heat generated. The springs are one thing, and lots of guys have airbags and overloads on their half-tons, but those add-ons don't do much for braking or wheel bearing improvements. With the 3/4 ton rear end swap you'll get better brakes, bearings and springs, at the cost of having 8 bolt rims on the back, and 5 bolt on the front. Personally, I'd do the rear end swap. The other thing about the 9" rear axle bearing design is that it is only pressed onto the axle and has a pressed on retainer. Axles have been known to slide out of the rearend if abused (mostly track racing, the Bud Moore Boss 302s had 9" rears modified to full floater). A full floater eliminates this because the axle is actually bolted to the hub, not just pressed on the bearing.

 

Modeleh, Thanks for the info so would the 3/4 ton be a straight swap or do i need to mess with drive lines or anything?
Thx

 

i had a buddy that had that happen on his off road truck... really all it was was a lift and some bigger tires.... and he had his passenger side shaft slide out while pulling a boat....

 

1957/67 F100 rear springs all exchange as they are same width (2 1/4") same length (Front: 24" > > > eye.bolt < < < 28" Rear).

F100 spring pacs available 1957/67: 5, 6, 9, 11, 13 leafs.

1961/67: The Ford 9" was standard equipment.

If you ordered Limited Slip, you got a Dana 44.

The Dana 60 with or without Limited Slip was also available as an option.

This Dana 60 (actually a 60.2) uses the same F100 wheels, has the same bolt circle: 5.50"

JMO: You can install air shocks, that'll save you the hassle of replacing the springs.

I wouldn't even consider installing a Dana 60 from a F250. For one thing, you'll have to carry two spares as the F250 has 8 lug wheels on a 6.50" bolt circle.

The F250's rear springs are 6" longer, so you'll have to change the spring hangers, the shackles, and you'll have to modify the driveshaft.

And if you do install a Dana 60, it must be from a 1972 or earlier F250. Otherwise you'll run into more problems.

1973 and later, the rear springs are 3" wide, the axle housing is wider as the 1973 F250 has a wider frame.

Then there's this:

Most Dana 60's have a 3.73-1 ratio, some are 4.10's. or 4.56's. Good luck finding a 3.54-1. While this ratio was available, everyone wants it, few find one.
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I've decoded about 50 of those F100 Dana 60's here on FTE, so there must be some around in yards.

Check with Don (cs65), when he returns from vacation, he may know of some.

 

Thanks bill, any way of id-ing the rear end? The frame & body are different so the vins aren't correct it's registered as a 250 but on a 100 frame. So i'm not sure what rear end is in it. Is the Dana heavier duty? Already have air shocks but if the rear end is sturdy enough i'd just put bags on it.
Thanks RCC

 

Bags were installed in coil springs, dunno of any bags for leafs.

Dana 44 & 60's have an inspection cover, the Ford 9" does not.

The Dana 44 is a weak sister, just ask any Nissan Titan owner.

Titan's all have Dana 44's, it's the weak link on these trucks.

The weight of the truck (over 5400 lbs) and towing capacity (9800 lbs.) does them in. The seals blow out, then the rear end disintigrates.

You're best best is to talk with Don, he knows these trucks, will give sage advice.

If I were you, I'd look at two options:

Installing a larger spring pac. What's there now? Prolly 5 leafs as most 1965/67's have these. Going to 9, 11 or 13 leafs will help.

Look for one of the Dana 60.2's that were installed in these F100's as an option...but be wary of the rear axle ratio.

 

What ratio should i be looking for? I'm trying to get a pic but i think this one is a 9in

 

another suggestion, you didn't mention if your truck has over load springs on it. if it doesn't go to your local pick and pull and get a set to put on yours. like the camper special for example. this will be a simple addto. LOL. these old trucks dont come apart easy the first time around. Dremil drill to fix the threads on your ubolts before you try and take it apart, a goodly supply of rust buster and a impact wrench will make the job cociderable easier. Dutch

 

That's what i've been wondering about. i'd have to get them off a 72 or earlier though right?

 

Im on vacation for a few more days Rob, but will get with you when I return to my normal routine...thanks for laying out all the pros and cons and differences in the springs and rear ends Bill...more food to think over...


- cs65