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Thread: Offset?

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    Offset?

    The distance from the left frame rail to engine mount is two inches farther than the same gap on the right side......

    How far off center are our engines pushed to the right? (hint: the easy answer is wrong!)

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    VCVC Member ShawnM's Avatar
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    Math quiz!

    That would mean its off center by 1". However I seem to recall its actually more than 1"?
    1966 G10 No Door with 250, 3 on the tree
    1964 Impala SS with 327 and Powerslide
    1949 Dodge Deluxe Fluid Drive
    1984 LeBaron Convertable

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    VCVC Member Kedvan4's Avatar
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    Smile

    Rear axle housing is also offset 1", one axle shaft longer than the other, something to keep in mind if you start thinking about rear end swap. Putting the housing in the center of the frame rails won't work for drive train alignment unless you change engine mount location. These vans are super simple until they get complicated.

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    The u-joints don't care about 1" offset. After all, they're offset more than that in the vertical plane from the trans to the diff. U-joints don't know up from down or right from left.

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    VCVC Charter Member Vanner68's Avatar
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    I beg to differ on the axle shafts. I replaced the shafts in the 10 bolt rear on my 65 and they are exactly the same length. (Yes, it is the original rear)
    Gregg Groff


    There's no place like 127.0.0.1

    1968 Chevy G20 108 panel Now with 454 power!

    1965 Chevy G10 panel- OHC Pontiac inline 6

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    VCVC Member cruzbox's Avatar
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    Our 67 had the same also.

    When I replaced the axles in our 12 bolt original rear end, the axles we’re the same length !
    Cruzbox

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    VCVC Member Kedvan4's Avatar
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    OK, mine is different

    Just went outside and measured on my 69/90 from input shaft to axle hub face, I assume this would be accurate. I got 28.5" on passenger side, 29.5 on drivers side. That would be 1/2 length difference on each. That would split the offset from the engine mount that is about 2" or 1" per side. Probably make it less noticeable looking at it and not be a vibration issue. I installed a narrowed 12 bolt on center in my 64/90" and the offset was very noticeable and concerned me however other than being kind of ugly, seems to function acceptably. That's what I got and why I posted what I did. I apologize if I steered anyone wrong, certainly not my intention.

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    VCVC Member jrinaman's Avatar
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    Quote Originally Posted by Vanner68 View Post
    I beg to differ on the axle shafts. I replaced the shafts in the 10 bolt rear on my 65 and they are exactly the same length. (Yes, it is the original rear)
    but do they both end centered in the center section? in other words, does a normal rear have equal length shafts on both sides?
    '64 chevy, 292 40 over, 206/526 cam, 2004r trans. 9.75:1, dual webbers, Langdon cast headers, 1.94 valves

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    VCVC Charter Member Vanner68's Avatar
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    Quote Originally Posted by jrinaman View Post
    but do they both end centered in the center section? in other words, does a normal rear have equal length shafts on both sides?
    Looks centered to me.

    Click image for larger version. 

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    Gregg Groff


    There's no place like 127.0.0.1

    1968 Chevy G20 108 panel Now with 454 power!

    1965 Chevy G10 panel- OHC Pontiac inline 6

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    VCVC Member m1dadio's Avatar
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    Just went through this .

    http://www.vcvc.org/showthread.php/3...line-vibration

    both by factory dimensional diagram and measuring my three vans; the engine/trans is offset to the right by 1" and so is the rear end pinion shaft. Because of the short driveshaft of the 90" van or shorter if you run a 700R4 trans , drive line alignment angles are s very important to be accurate or you will get vibrations, unlike other vehicles with longer drive shafts that can get away with sloppy angles. I discovered a measuring tape just dosnt cut it here, when I used my laser I found out my install was wrong by 3/4" that could not be seen with a tape.

    M1D
    Don't ask me!! I'm still stuck on "who am I?" and "What do I want?"

    1965 G10 all window "ChevyVan" with 1988 305 Tuned port injection V8, 700R4, 1980 10 bolt posi.
    1968 G10 "sportVan Custom" under construction.

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    That's right. It's the angles that matter, not the offset. Within reason, of course. After all, the whole purpose of a u-joint is to accommodate offset.

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    The offset that matters for the differential is the offset of the pinion yoke from center..... The posi I'm using from a 91 wagon is 1/2" to the right, so that is where I'm going to set my engine....
    Small offset differences of 3 degrees or less should be okay in both horizontal and vertical planes as long as the trajectories of the trans and differential shafts are on parallel planes..... both u-joints will be the same degrees from straight if this has been accomplished...

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