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Driveshaft angle in tunnel

Posted By: johnnycuda

Driveshaft angle in tunnel - 11/03/16 07:40 PM

Hey guys, building a 69 Valiant, 408 with a A500 trans,8.75 rear, slant-6 car, using the TD Performance engine mount converison kit.
I remember seeing somewhere about the angle of the driveshaft in the tunnel, not talking about pinion angle, but the angle from the tailshaft to the rear yoke.
The article I saw said Mopar had the driveshaft at a angle in the tunnel to help with vibration, obviously the pinion is offset in the car at the rear, so is the driveshaft at a angle in the tunnel front to back. I haven't made the trans crossmember yet, using a T400 mount.
The car had no motor/trans when I got it. Thanks in advance.
Posted By: Dave Hall

Re: Driveshaft angle in tunnel - 11/03/16 08:56 PM

If you are asking if the angle is side to side, looking from a plan(overhead) view, no. The whole shebang is moved to the passenger side.
Posted By: CMcAllister

Re: Driveshaft angle in tunnel - 11/03/16 09:15 PM

Originally Posted By Dave Hall
If you are asking if the angle is side to side, looking from a plan(overhead) view, no. The whole shebang is moved to the passenger side.


This. Straight line from front of crank to the pinion. The only reason for angle on the vertical axis is to allow for suspension movement.

That doesn't mean that I haven't seen it run non-parallel to the C-L of the car due to a mis-match of engine and/or pinion centerline locations. And if it's not too extreme is probably not a huge problem on most cars. But don't build the car that way if it can be helped.
Posted By: johnnycuda

Re: Driveshaft angle in tunnel - 11/03/16 10:06 PM

Thats what I thought, thanks.
It has a stock width A-body 8.75 with the perches moved in 3", bought it that way, going to wait until I can get it on the lift to build the crossmember and make sure all is straight.
The tailshaft is slightly towards the drivers side at the moment, but the mounts aren't tight and no crossmemeber of course.
Posted By: Dave Hall

Re: Driveshaft angle in tunnel - 11/04/16 08:30 AM

I have a buddy that has a ladder bar Charger that was front halfed after the back half and the driveshaft is at a slight angle towards the pass. side. No problems with more than a 1000 runs at low 9's and big wheelies.
Posted By: Just-a-dart

Re: Driveshaft angle in tunnel - 11/04/16 04:03 PM

Johnny when I put the a500 in my Dart I centered it in the driveshaft tunnel. It was a fun set up. If you can get a empty case it makes set up a lot easier.
Posted By: gregsdart

Re: Driveshaft angle in tunnel - 11/04/16 05:11 PM

It is not important for the transmission and differential to be perfectly in line In the horizontal. As long as the transmission and differential are parallel but offset, the drive shaft will be happy. I have an 8.8 Ford which is offset in a dart and there is no vibration at any speed. A drive shaft doesn't know or care which way it is offset. The U-joints compensate.
Posted By: johnnycuda

Re: Driveshaft angle in tunnel - 11/04/16 06:09 PM

Thanks guys, once I take it to my buddy's shop and put it on the hoist, will be easier to align and finalize the mounts etc. and set pinion angle.

Should be a fun ride, 408 with RHS heads,.540/.556 cam, 2500 convertor in the A500 (low first gear) 3.73 rear, 275/60 drag radials, car should be light, manual steering/brakes, bench seat, was a slant-6 stripper.
Posted By: Just-a-dart

Re: Driveshaft angle in tunnel - 11/04/16 06:21 PM


Johnny you might want to get a little more rear gear 3.73 is a little flat in overdrive unless the converter is real tight.
Posted By: johnnycuda

Re: Driveshaft angle in tunnel - 11/04/16 06:30 PM

Yep, I had A-1 build a 11", should be around 2500 stall, my buddy Darren from ProTrans has a similiar combo in his wife's Demon, so had them build the same convertor for mine. I figure the car should run high 11's on the motor, plan to drive to Fontana once in a while, run it and drive home...hopefully, lol. I was actually looking for 3.91's when I found the 3.73's at Woodley a year ago on a great deal, figured I'd try them and see how it does, swap out if needed.
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