Driveshaft length

[Dr. Righteous]

Hey guys
I will have to get a custom driveshaft made or try to scratch a used one for my engine/tranny swap in my '69 Coronet.
The 318 and the 904 comes out. I already installed a 83/4 posi rear in it. Now, what driveshaft will I need with my 383/727 install?

[340king]

Hey Doc, I would slip a spare trans yoke into your trans and set it up at least 1" from bottoming. (You may want to check this figure with a tech manual as it has been some time since I have done this.) Then measure from the back/end of the u-joint opening to the rear end yoke u-joint cup. This will be the center to center length that you are looking for. Do this with the car near ride height and with both yokes horizontal. You can use this length while cruising the salvage yards or having a custom shaft made.

[hemivaliant]

Doc,
Per my '69 Plymouth Service Manual the size drive shaft you need for your combination is 51.50". The length is measured from the centerline of the front yoke bearing bores to the centerline of the rear bearing bores. The diameter of the shaft should be at least 3.00".

Best of luck with your project.


HV

[speedy]

I just had one shortend last summer i went from a 7.250 to a 8.250 sure grip rear end . they cut it welded it and ballenced it for less then 50 bucks.

[Dr. Righteous]

Thanks for the info guys.
I called the drive line shop and they regretted to inform me that they couldn't get the large MoPar yoke anymore only the small one(small block slant6). So they can't build me a 'big block' drive shaft. I will have to take my existing drive shaft and have it shortened and then use those very expensive combo U-Joints.

[Larry S.]

The Mopar Performance catalog shows everything you need to build a large u-joint driveshaft except the trans slip yoke. It shouldn't be to hard to find the slip yoke.

[Dr. Righteous]

AHHH!!
I didn't even think of the MP catalog for that. I already have the slip yoke.
Thanks Larry S.