74 Dart drive shaft help

Mopar Racers Forum

  1. No rush

    No rush Active Member

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    Hi all
    I am building a 74 dodge dart into a bit of a drag car.
    Has a 500ci stroker motor on methanol, powerglide and a 9 inch. Car is mini tubbed with the leafspring inboreded and 35 splines axles and 325 tyres.

    I am looking at getting a tailshaft made, will the car require a one or two piece tail shaft?

    Drive shaft measurements are
    Drive shaft:
    L 151.5cm (from pinon bolt face to seal)
    Carrier 91.8mm
    U bolts 42.6mm
    27 splines
    Engine Is probaly going to make 650-700hp and turn at 7500rpm.

    So what do you guys reckon?

    Edit: I will add that there are two driveshaft manufacturers in my area, one will only build a two piece saying it a to risky to run a single piece.
    The other said single piece will be fine.
     
    Last edited: Dec 3, 2019
  2. 73smallblock

    73smallblock Well-Known Member

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    What you have posted 151.5cm is like 59.xx in. Usually shops want to measured from center of ujoint to tip of tail shaft or some even want you to buy a sip yoke and bottom it out in the trans and measure it center to center. That's actually going to make your done dimension shorter. The second way is the way we did it when I worked at a drive line shop.

    Any way you look at it your going to want to go 1350 ujoints. One piece would be fine. If it's made from steel they probably are going to want to make it out of 3 1/2in tubing even though 3in .095 or even .083 should be just fine.
     
  3. Locomotion

    Locomotion Well-Known Member

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    I never even heard of anyone using a 2-piece driveshaft in a conventional drag car!

    As you probably know, driveshaft angles are critical. As for u-joints, IMO Spicer solid u-joints are the best, 1350, as mentioned in the previous post. A forged or billet yoke on the rear end is also helpful. There are also different levels of tubing - mild steel, seamless & chrome-moly.
     
  4. No rush

    No rush Active Member

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    Thanks for the replies.
    From what you guys are saying it sounds like the second quote I got is the more legit one.
    This is what they said.
    1 pce driveshaft. Powerglide to 9". 1515mm seal to center of uni.
    Both options will be 1350 series heavy duty solid cross Dana Spicer universal joints, hand picked, forged weld yokes and 3.5" seamless tube.
    Option 1 with forged slip yoke $less
    Option 2 with forged fully machined slip yoke $more

    We can use 1310 Series seamed tube and high performance joints to save some $, but based on what you have advised your power is I would stay with 1350 series.
     
  5. No rush

    No rush Active Member

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  6. 73smallblock

    73smallblock Well-Known Member

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    I understand what they are saying but you are not the first one to run a driveshaft that long. There is a guy local to me that runs in the 8's (1/4 mile) with a 572 in a 70 roadrunner. He also has a glide but I can't remember if it was a 9" or a Dana. The shaft was something like 62" center. 3 1/2 dom tube with spicer parts, never had an issue. That's just one of countless examples.
     
  7. No rush

    No rush Active Member

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    That's true,
    I just wanted to see what other A bodies run with a similar combo, think there would be heaps out there that are fast.

    It seems posting what drive shift setup they are running is a popular thing to do.
    I would hate to have spent all this time and money on my cars for the drive shaft to fail and damage stuff.
     
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