Pre Stepdown Modern Rear End

Uncle Josh

Anybody know some equivalent higher speed rear ends to fit a 39? I have a list for stepdown but they are about 5 in narrower. Thanx.

RL Chilton

Uncle Josh-

Are you saying a step-down is 5" narrower than a '39?

Wisconsin Hud

I used a 1976 Ford Granada rear end on my 1935 Hudson8.It was almost an exact match for the original rear end. All we had to change was the pads.I believe these mid seventies ford 8 inch rear ends are common and inexpensive. I bought the Granada for $800 and drove it for a few years before using the drive train and alot of other parts in the 35.

Uncle Josh

RL Chilton wrote:

Uncle Josh-

Are you saying a step-down is 5" narrower than a '39?

That's what my measuring stick says. Had to get the wheels inside the fender skirts but it worked out good for racing.

Old Fogey UK

That's useful information about Ford Granada rear ends for us 34 and 35 Hudson 8 owners. How can I get more detailed information on this conversion, please ?

MikeWA

I haven't done a Hudson, but have done others, and they're all pretty much the same process- Take out the Hudson rear, set it beside the replacement, and move the flat brackets that the springs sit on, to match the spacing on the Hudson. And that's pretty much it, other than re-attaching brake lines and driveshaft.

jjbubaboy

I helped a friend of mine do one in his car 'of a different make'.
He went and bought a couple spring perchs from a trailer supply store that way he could leave the original rear intact.
He used a couple magnetic angle gauges to get the right angle on the new brackets and welded them on and we threw it in. Took about a day to do it. He says so far so good....
Jeff

Browniepetersen

I have a Lincoln rearend in my 36. The modifications were completed before I bought the car so all we had to do was shorten and balance the drive shaft. My 28 Essex that I am building has a Mecury Bobcat rear end in it. All we had to do to that one was move the pads.

jjbubaboy

Well that is interesting on the Granada.
I went today and measured a Ford 8.8 from a 90ish ( he said) Mustang. The overall length was within 1" so no problem. But I then discovered the pinion offset was not centered like my Hudson rear. It was 1" off to the left. Dont think thats gonna work as it will put the driveline out of alignment. So guess I will keep looking....
Not to mention it was a Craigslist posting and NOT as 'clean' or gearing what he claimed it was. LET THE BUYER BEWARE!
Jeff

super651

I used a diff from a 1968-69 Roadrunner in my 46 4-door and it fit just fine,just reposition the diff pads. mine is a 3.36 ratio ( use the Mopar Corpation diff) built by Mopar.
Hope this helps Rudy

4Hud

On my '37 Terraplane I used a diff. from a 65 Dodge 6 cyl. std. trans. I think it is 3.73 ratio. It was off center also, it's o.k. as long as the driveshaft doesn't rub on the x-frame opening. The important thing is to make sure all angles are the same degree on each end of the driveshaft to prevent bad vibes.

Courtesy Man

My 1947 Hudson pick-up has some alterations including a 1971 Ford 9 inch Cougar rear end - drum to drum and with the spring perches welded further inboard it is a great fit.Running a 1956 Hornet engine the 3 to 1 ratio did not work with the Hudson overdrive so I swapped the "pumpkin " for 350 to 1 which is better but 370 or 411 would be better.
The 350 however will run it over 80 mph - course it is unstoppable at that speed ! The wheel bolt pattern is same as Hudson and I run Hudson sedan 15 inch wheels. Don't know if this would work on a 1939 however. Gert Kristiansen Deseret Chapter.

Lee ODell

The 90's T-Bird 8.8 rear end is the same as Mustang except it has 5 studs on the axle flange. The axles and brake drums are interchangeable with Mustang 8.8 rear end. Must use T-Bird brake drums if putting T-Bird axles in Mustang houseing because of slight difference in axle length.

jjbubaboy

All good info!
Granada rears are not easy to come by as I have discovered, nor are 9"-unless you have lotsa extra $$.
I like the idea of the T-Bird so as to keep the same wheel bolt pattern. That too is one of my goals.
8" rearends of various models dont seem to be as pricey nor do the 8 1/4 mopars.
Now just have to hunt for correct length and gear ratio I want...hunt, measure, hunt, measure..
Jeff

Ol racer

FYI
Ive narrowed Ford 9" rear tubes to be equal width on the Racer but kept the slight offset on my St Rod applications and have had no driveline angularity problem drive shaft running slightly left. It may lose a little inertia thru the joints but neglible.

Lee ODell

The 90's T-Bird 8.8 rear end is the same as Mustang except it has 5 studs on the axle flange. The axles and brake drums are interchangeable with Mustang 8.8 rear end. Must use T-Bird brake drums if putting T-Bird axles in Mustang houseing because of slight difference in axle length.

I believe this holds true with the 80's T-Birds also. Before T-Bird indepentent rear suspension.

junkcarfann

I have been down this road twice, first with a 1940 Hudson, next with a 36. With the 1940, I searched and searched, and finally found a 1966 Plymouth axle. Big dollars, brakes needed complete rebuilding.

Therefore, unless you have lots of $$$, forget about the old Ford 9" rears, and those from various MoPars from the 1960-1970's; those are now antiques, and big money, plus they need rebuilding. For some reason, every time this topic pops up, the answer is to use what is now an antique rear, when there is a better way: modern (read cheap) rears are far more readily available, and do not need rebuilding, de-rusting, etc.

The way to go with a 36 car is to use a Ford Ranger style rear. They are known as Ford 8.8". I put one from a 2006 Explorer in a 36 car,and it was 1/2 inch narrower, which is 1/4" on each side. No problem there.

The amazing thing is that the thing almost bolted in. I had a welding guy burn off the Ford spring hangars, etc, and fabricate new spring perches, using the Hudson axle as a guide.

After changing the front yoke, the Hudson U-joint fit...the driveshaft was exactly the right length. The Hudson hydraulic brake Tee also fit in the Ford hole, was only 1/2 inch off, and the threads were the same! I used a Lokar universal e-brake kit for hot rods to get that hooked up.

You just need to make sure that the angle of the pinon is angled down to the same degree as the Hudson angle was, otherwise you will have vibrations problems.

The best thing is to contact the local rear axle shop. All cities have at least one, a specialist who just rebuilds rear axles for dealers, etc, kind of like a root-canal dentist just does that, upon referrals from regular dentists. They know all about install issues, as does the local hot-rod fabrication shop. Also, the local driveshaft shop, where that is all they do...They know all about the pinion angle situation.

But please stop with the suggestion to use old 1960 mopars, Ford 9'', etc. Those were good choices 30 or so years ago, but now those cars a collectible antiques, thus their parts are made from unobtanium, and are $$$$. Even 1990 Mustangs, T-birds, etc, are getting hard to locate.

The modern 8.8 Fords (still being made..you don't have to go to early 1990 cars) fit width-wise, have the same bolt pattern as Hudson, and junkyards literally have dozens of them, from various cars/suvs/trucks, with various widths, with plenty of ratios available.

chopperchuck

OK,here's some info.for 4 1/2 bolt patterns.if i knew how wide yours is i help some more{i hope this helps}
________________________________________________
5 on 4-1/2 (114.3 mm)
AMC Gremlin, Hornet, Pacer, Javelin, Matator, AMX
AMC - most models (exc. Jeep) '40-'89
Chrysler/DeSoto - all full size RWD cars (exc. Imperial) '37-'89
Datsun/Nissan - 1600-2000 '65-'73
- 300ZX, 200SX V6 (some) to '89
Dodge van
Dodge 1/2 ton P.U.
Dodge - all full size cars & P.U.'s '37-'89---[WATCH OUT for 5 on 5 on some]
- Dart, Demon, Swinger '73-'80
Ford 1/2 ton van
Ford Granada, Monarch
Ford - All full size cars '49-'72; '79-'85
- Fairlane '62-'79
- T-Bird '55-'71; '77-'79
- Mustang 5-bolt '65-'73
- Maverick 5-bolt all
- Mustang SVO '85-'86
- Ranchero '68-'84
- Aerostar, Probe, Bronco II/Ranger to '89
Hudson - all '48-'56
Lincoln - all '70-'72; '80-'89
Mazda - RX7 Turbo, 626, 929, MX6 '86-'89
Mercury - all full size cars '52-'54; '61-'72; '79-'85
- Cougar '67-'79
Mopar '73-up "A" body
Plymouth - all full size cars '37-'89
- Barracuda '70-'74
- Duster, Valiant, Volare '73-'80
Pontiac - Tempest, LeMans '61-'63
Studebaker - all '51-'66
Toyota Crown, Hilux P.U.Toyota - 2WD P.U. '69-'89
- Supra Turbo '86-'89
Volvo 122, 1800

chopperchuck

Ford
Outside
Width Year Model
56.50 1969-1977 Maverick 8"
57.00 1974-1978 Mustang II 8"
57.25 1957-1959 Ford, Ranchero, Station Wagon
57.25 1965-1966 Mustang
58.00 1964-1965 Falcon
58.00 1977-1981 Granada/Versailles
58.50 1977-1981 Versailles
59.25 1967-1970 Mustang, Fairlane, Comet, Cougar
60.00 1967 Cougar
60.00 1958-1960 Edsel
61.00 1964-1971 Ford Full Size
61.00 1949-1951 Mercury
61.25 1960-1964 Ford Full Size
61.25 1971-1973 Mustang
61.25 1967-1973 Torino, Ranchero, Fairlane
63.00 1970-1979 Ranchero & Torino
63.00 1972-1979 Ford Full Size & Intermediate
63.50 1967 Fairlane (Coil Springs)

chopperchuck

Mopar
Outside
Width Year Model
55.60 1960-1976 7 1/4 A-body
55.60 1973-1976 8 1/4 A-body
55.60 1966-1972 8 3/4 A-body
55.60 All 8 3/4 A-body
56.00 1932-1934 All Mopars
57.40 1963-1972 7 1/4 A-body
58.54 All 8 1/4 F-body
58.54 All 8 1/4 M-body
58.54 All 8 1/4 J-body
59.00 1935-1936 All Mopars
59.14 1966-1970 9 3/4 B-body
59.20 1962-1970 8 3/4 B-body
60.00 1937-1948 All Mopars
60.70 All 8 3/4 E-body
60.70 All 9 3/4 E-body
62.00 All 8 1/4 B-body
62.00 1971-1974 8 3/4 B-body
62.00 All 9 1/4 B-body
63.40 All 8 1/4 C-body
63.40 1971-1974 8 3/4 B-body S.W.
63.40 All 9 1/4 C-body

chopperchuck

I HOPE i didn't muddy the waters to much with all this info---Chuck

Uncle Josh

Got t'thinkin about my earlier post. Combo of early data and bad memory maybe. Plus was measuring to inside of backing plate which has several different surfaces. So I measured a couple of rear ends the best I could with a tape measure the other day. To outside of hub where the rim touches.

54 Super Wasp (All stepdown's should be the same.) 57 inches
39 Country Club 60 1/4

faustmb

I have a rear end from a 99 explorer waiting to go in my 47 truck. It is disk brake, traction loc(posi), same bolt pattern, an cost $125. The width is very close, with 1/2" I think. It is an 8.8 which is a very good axle.

Around 2000 they went to independent rear, so even these are getting snatched up and harder to find.

I'll post pics when I finally get it installed.

bob ward

Many thanks chopperchuck, your info saves a lot of time wandering around a wrecking yard with a tape measure.

faustmb

Rick,

I looked into this and was told that rear disk only would work, but it is obviously not ideal. I do plan to install front disks soon. I have a complete setup from a 94 mustang I as going to work with, but the disks are too large to keep oe wheels. The plus side is the parts are cheap, common, and the brakes would be very beefy

Matt

faustmb

Sorry, I wasn't too clear. Rear disk only, front would still be drum. It doesn't sound like a good idea, but doing some research it s plausible and should be ok. I do not plan to do it however, I will do the entire swap at once.

chopperchuck

Thanks i was going to post more info,but was afraid of mudding up the waters to much,i plan on using a jeep cherokee rear,you can get em in drum or disc W/many ratios also can get em open or closed {possi or non-posi}--chuck

chopperchuck

4From what I understand, many Jeep owners are doing Exploreratorys (swapping out their Jeep rearends for Explorer rearends, which they claim are more dependable and rugged).


Only if your going 4X4ing,but on the street they're pretty good {got 1 with over 170,xxx on it}-chuck