1955 Thunderbird rear axle dimensions

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. I wonder why the 1955 Thunderbird was built with the drive shaft out of alignment. Currie has suggested building with no 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)

schematic chassis red.jpg
 
Many people have told me the side offset was Fords idea to extend the life of the u-joints as the needle bearings are always turning. Many u-joints wear out because they stay In one place and wear a grove in the x-pins. Makes sense, but most cars don’t have side offset . If you have room in tunnel, don’t bother with offset. Vertical offset is critical, to stop vibration, usually 3 degrees
 
Lorne, Thank you for the input.

This build will work at zero lateral offset. Regarding vertical: 5 deg offset is a number that Currie came up with. I am wondering if there is a benefit to reducing the vertical offset to 3 deg.



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3 degrees is rule of thumb and I would think 5 Degrees would be max. You will have no problem between 11/2 to 5 degrees. Only tech part is welding spring saddles in proper location . I would try for 3 degrees to be safe. Check 3 times weld once. Maybe Currie has jeg to weld them on. Lots to consider spring arch and shackle length , better to weld self if you have competent welder. Best of luck, Lorne
 
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