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By Brent - 4 Years Ago
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I am planning to purchase a Currie or Quick Performance rear axle. I have attached a Ford Engineering drawing of the '55 Thunderbird chassis which shows the pinion offset which moves it from being aligned with the crank and trans, everything that I have read indicates offset is used when engines are mounted off center to keep the drivetrain in a straight line. Apparently the 1955 Thunderbird was built with the drive shaft out of alignment. Currie suggests building with zero offset.
Anyone have these numbers documented?
1. Wheel mount surface, outside of brake face to outside of brake face:
(I have come with 57.5”)
2. Pinon offset, typically to passenger side:
(I get approx1.75” to passenger side. Have any of you had an axle built with no offset? I want to be sure I am not overlooking some need for the offset.)
3. Center of perch to center of perch, also note if it is above or below the tube center line:
(Drawing indicates 42.187) (I get 1 3/16” down)
4. Pinion angle:
(I have come up with 5 deg down)
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By DryLakesRacer - 4 Years Ago
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If the 9” was the rear end in the 57 like the big cars and they were on the same chassis, why not have it built to the 57 specs? Unless you want one where you can change pumpkins I would look to new Fords like the Ranger and Explorer 8.8. Drums and discs are available. I am not familiar with Quick Performance but Currie is very proud of their rear ends.
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By miker - 4 Years Ago
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The 57 bird used a 9", and while the rear springs may have varied from 55-56-57 I'm pretty sure the front hangers were the same, so the rear end dimensions should be the same. Those are big heavy rear axles unless your going real high horsepower and big tires. The truck axles and larger bearings in the Dana 44 bolt right in a bird. And the Viper used the Dana 44 gear set, among others.
DLR is right about more modern rear ends.
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By Vic Correnti - 4 Years Ago
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This got me thinking since I changed my 2x4 intake from a Edelbrock 255 to a 257 a few years ago I have had the front of the oval aftermarket air cleaner hit the hood on the right side at the front area of the scoop. The engine on my 55 bird is off center by one inch to the right (passenger side). The transmission tailshaft at the driveshaft is 1/2 inch to the right. I always thought that was because of the ring and pinion. My bird has a 58 Ford 9 inch housing which I believe was a 1/4-1/2 inch wider then the original Dana. The pinion centerline measures on center. These measurements were measured to the frame. So is the 58 housing different then the Dana? Could someone measure a stock Dana pinion location so I can get some sleep.
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By Brent - 4 Years Ago
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My stock Dana pinion is offset 1.75" to the passenger side, I measured to the springs. Lorne, at this link, says Ford offset laterally to preserve needle bearings.
The engineering drawings show engine and trans centered with pinion offset. Maybe you can tweak the engine over with the steady-rests.
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By Vic Correnti - 4 Years Ago
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I have taken advantage of tweeking the steady rests but it didn't change much. The front engine mount locates the motor pretty rigidly. Will your rear include a posi unit like a Eatin Detroit Truetrac? I have had bad luck with mine and they will not stand behind it and no repair parts are available either. I got lucky and caught mine before it took out the whole pumpkin.
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By Brent - 4 Years Ago
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Thank you for the info. I had planned to run an Eaton TrueTrac. What was the problem you encountered?
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By Vic Correnti - 4 Years Ago
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It is about 3 or 4 years old and 2 years ago it started making a clicking noise going around corners. So this winter I thought I could send it to Eaton and have it fixed and they said they don't fix them. So I took it apart and found this gear that drives one of the axles to have almost all every tooth cracked and everything else looked great. So I call them back to plead for a gear, even a used gear and was told no way and they are usually totally ruined when they go bad. Do some googling and I'm not alone. Some of the guys are recommending the Eaton Posi because they can be rebuilt. Are you planning on drag racing or just street use. Is your car a stick or an automatic? I'm thinking an automatic would be less stressful on the Truecrap. I hit the track 4 or 5 times a year and locally around town.
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By MoonShadow - 4 Years Ago
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The guide we used to set up of my roadster was no more than a total of 5 degrees out of true. Up down, right left it all counts. My transmission output shaft is centered and the Bronco rearend is offset but it still came within specs.
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By DryLakesRacer - 4 Years Ago
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I know it’s not a true video of something we would normally not do; if you go on you tube and view a rear end movement of an IMCA modified you would never worry about alignment again. I’ve read where a u-joint can move thru 22 degrees of motion. Not say it would last long but that is the specs I’ve read. We run dirt car and have never had a problem with a good quality joint.
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By Brent - 4 Years Ago
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Looked around for alternatives to the True-Trac. Spoke with Strange, they manufacture the Strange S-Trac which carries a Lifetime Warranty (35 spline only). They recommend the True-Trac for my 2700lb car 400hp C4 mild torque 27" tire setup. Strange sells lots of them to users and builders (lots at a time). The S-Trac is to much for my setup but for your wheel stands, maybe worth a look, Vic.
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By Vic Correnti - 4 Years Ago
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Brent, thanks for the info. Here's my bad luck, last December I ordered another Truetrac and installed it in my nodular 4:11 Moser figuring on getting my other one fixed for a spare or sell it. I installed a new clutch setup that slips on launch so maybe I won't hurt the new one.
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By charliemccraney - 4 Years Ago
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I got a Truetrac a few years ago. I hope it doesn't fail me. I'm also not putting nearly as much power through it. At that time, I didn't come across anything negative about it.
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By Vic Correnti - 4 Years Ago
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Charlie,
I would have thought going straight wouldn't be as hard on it as going around corners but what do I know. Now that I think about it, turning made the grabbing and snapping noises. Other then the axle gear being cracked it looks brand new inside.
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By pegleg - 4 Years Ago
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I've run one in the Red F code for 13-14 years, street and drags, Still working good. Don't have Vic's horsepower though!!
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By tbirddragracer - 4 Years Ago
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I ran a Strange 35 spline axle with 4:56 gears in my '56 T-Bird race car for years, no problem.
Ernie Phillips
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