I would like to install a 9" ford in my 1965 F-100 . I have a C-6 being rebuilt , for my 352 stoked to 381 ci bored . 010 w 390 crank & rods installed.

 

Oh no, what is the best car- truck axle to use . W/ out doing to much work to it.

 

Doesn't it already have a 9" in it?
I thought all 1/2 ton trucks from 59-66 had the same diff?
How `bout it, guys?

 

I'm going to have to second the notion that it probably already has the 9" rear end. One quick way to tell is if you can NOT put a socket with an extension straight on the bolt that is just to the left of the bottom center bolt (facing the rear of the truck), it's a 9". The 8" rear ends allowed easy access and removal of those specific bolts.
Post your tag info off the door and we can tell what should even be in there......
Welcome aboard!

--Mike

 

well i have a 66 f-100 4x4 wih a stock spicer 44 in the rear

 

Nope 4x2 has a 8.9 rear axle w/ rear cover plate aprox 10 bolts I have 2 1965 F-100 both rear axles are the same. It now has a cruseomatic soon a C-6. Don

 

Sounds like its NOT a Ford 9" rear. Bummer, as that makes swapping rear ratios a lot harder.

As to what ratio you want, well you need to decide what you want to do. If you like cruising at highway speeds, then go relatively low, say 3.00 or 3.25. But given your description of your motor, you sound like you want to really get off the line and you're not afraid to rev her up. In which case a 3.75 or even a 4.11 might be the way to go.

I would suggest you post this question to the 352 engine forum as well. I am not personally aquainted with the power band/torque/mas RPM characteristics of your engine. They will be. Keep in mind that the top gear in your C6 is 1:1, and the lower gears are spread out from about 3.5:1 up. The only practical consideration re your C6 is that it is a heavy enough tranny to handle some serious torque -- the higher the rear, the more the tranny gets "worked". But all in all, unless you have an OD or a granny gear, your rear end choice depends on the factors I first described.

Good luck.....

 

I also thought they were all 9" axles - you learn something new every day.

Easy swap is to find one from an '57 - '72 half ton pickup. Should be a direct bolt in exchange.

 

what would a 66' 4x2 f250 have in it. I know its a 4:56 gear but dont know what size axle, and its toooooo dang cold to get out there with a socket to test it

 

Yo, Ford had been using 9" for 10 or more years in 65. We don't know what some po may have swapped in, but the truck came with a 9".

voodoo, The 250s & 350s came with Dana rear gears (8 lug).

4X4 front axles are Danas too.

hope this helps

John

 

Guys,

FoMoCo uses both Dana 40 series, salisbury type(rear loader) & Ford 9" Hotchkiss (front loader) rears depending on engine OEM put in truck at assembly plant. I believe you'll find 223 & 240 I-6s came with Dana 40 series & V8's generally came with Ford 9". through 1966 anyway.

As for what rear to use, I'd recommend looking for a 9" out of a 74-79 F 100-150 Series w/ Big Inch V8, an F150 V8 LWB or any Camper/Trailer special. The F150 camper & trailer Spcl will have 3" X 11" Drum Brakes. All of these rears should be 31 spline(big dia axles) and the trux with letter designation rear axle IDs were traction devices when they left OEM Assembly Plant.

These 74 - 79 rears are direct bolt in, Park Brake cables hook up using OEM parts w/out conversions, generally brake line dia's are the same, altho I have had to upgrade a few times to larger dia Hydraulic lines, like in a 62 Integral Bed (Uni) I did and a 65 Plain Jane F100 w/240 I-6 & 3spd O/D. Most others were same tho.

Those with number IDs were all Open Leg, (non traction device) rears. Altho, the desirable 4 pinion 9" x 31 Spline has a Number ID, I'd really consider it to be a suitable, non friction or ratchet style "traction device" differential. I've got one & if I back straight up 10"-0" or so before I launch, both axles engage and both tires light up, just like a traction device rear will do.

F250 & up single wheel will be a Dana 50 or 60 and have the eight lug pattern. Youdo not want this rear unless you have an F250 or 350 single wheel truck!

If going hunting rears look up rear axle codes in an OEM service manual for 74-79. You can pick & choose rear you want by looking for the appropriate number/letter ID on door Data plate. Be sure & double check w/ ID tag on differential case mounting bolt to be sure. If the rear end is OEM, Virgin, or was worked on by Ford certified tech, Axle ID tag should be in 2:00 position when facing pinion flange. Without that, rear may be a gamble.

One last point on what to look for. . . Some rear end Differential Cases were Nodular Castings. Obviously Nodular is better choice. There's 2 ways to ID nodular cast housings. Over counter units will have a large, maybe 1"-1.25" stylized N cast just above pinion collar bore. The other Nodular casting has a waffle looking multiple ridged reinforcing web system cast on the front of case. It has at least 2 vertical ribs and 3 or more vertical webs and/or will have "WAR" casting ID.

Or you can trust a guy that wants to sell you a rear end he has for sale. But Inquiring minds want to know, and knowing allows informed decisions. Generally here, rears I described as most desirable go for between $150 & $200 complete, depending on if they are Traction Device equipped and which one, or not traction device and other variables.

Oh yeah, 9" rears are easily rebuilt by any qualified technician, or Knowledgable novice with the right tools & techniques. It's not "Rocket surgery" # is mostly common sense. In fact I've set many a 9" Ford rear using carbon paper from a "snap out" multi copy invoice when I did not have a dial indicator handy.

Also mild or moderate "picturing" on tooth faces can be erased! Some wear does not rule out a good unit, and can lead to lower pricing with provision nothing is actually broken inside, of course.

So go forth, seek w/ knowledge & you shall find.... good Hunting and good luck

FBp

 

Here's a critical addendum on FoMoCo rear end swapping. . . .

Any of you who've ever pulled a FoMoCo rear end out of a 60's or 70s Ford, & taken the time to look at the U-Bolts closely should have noticed the inside radius of the OEM U-Bolts are flattened at the point the contact the axle tube. THis is engineered into U-Bolt design for a good reason.

Aftermarket U-Bolts do NOT have this important unique feature FoMoCo incorporated in the OEM design. Without the flattened inside radius, the rounded stock will crimp or kink axle housing tube on both sides of the spring perch when properly torqued.
These dual crimps/ kinks act like 1st couple of turns of a tubing cutter and totally wipe out axle tube structural integrity. Bear in mind when rear is planting power to pavement force is borne by axle tubes. They can give at these crimped/ kinked points and get out of alignment, becoming untrue, or if you make real power, they can actually fail & tear/break there.

Take the time to "un-wind" OEM nuts off OEM U bolts either on your own slick, or on the donor you get your rear from, or have the salvage yard "Un-Wind" them instead of cuting them. I do!

Some good penetrant, a wire brush on a cordless drill, a couple nuts with hack saw X cuts across them, or a die, or 1/2" thread chaser rundown & up the U Bolts makes removing the OEM nuts easy. It's worth the effort IMHO

FBp

 

I do know the gear size is 3.54 in rear axle 3rd went out in atlanta - drove home in 1st & 2nd gear at 50 - 55 mph to Northern Va. dang old cruseomatic. But it did bring me home Bought it in Birmingham Ala. at airport it was towed there on car hauler from Tupelo, Miss. Where it was a show truck. And towed to car shows. Adv. 12 - 14 MPG coming back , Don

 

I do know the gear size is 3.54 in rear axle 3rd went out in atlanta - drove home in 1st & 2nd gear at 50 - 55 mph to Northern Va. dang old cruseomatic. But it did bring me home Bought it in Birmingham Ala. at airport it was towed there on car hauler from Tupelo, Miss. Where it was a show truck. And towed to car shows. Adv. 12 - 14 MPG coming back , I will run 3.73 or 4.11 in it. Don

 

I would look for a 64-72 9" rearend. Then you can get about any gear ratio you want. It will be a a 28 spline center section.
If you go to the 73-79 rearends, it will have 31 spline axles and the rearend will be wider than the 65's stock rearend.