Early Dart Drive Shaft Length - 340/727 w/8.25"?

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socal_65dartgt

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Help! Does anyone have a driveshaft measurement for an early Dart with a 340 - 727 combo and and a 8.25" rear? It is for my 1965 and I still have the 225/904 with flange/ball & trunion and 7.25". I need to get one ordered from the local driveshaft shop and I am squeezed for lift time. Haven't got a chance to mock it up for measurements.

I found the following from: http://www.autohobbydigest.com/tables.php?17_driveshafts_slip_yoke
Part #: 2660607, Year:1966, Diameter: 3", Drive shaft Length:56.61", Trans: 904/833, Rear: 7.25", Engines: 170/225/273, Body: Dart,

According to : http://tciconverters.net/Products/TechInfo/converter_dims_tables.htm the difference in length between a small block 727 (34 3/8") vs. 904 (30 3/4") is (- 3 5/8").

According to http://www.bigblockdart.com/techpages/diffchart.shtml the difference in length between axle center line to rear universal joint for 7.25" (10.09") vs. 8.25" (11.69") is (- 1.6")

So my calculated guess is 56.61" - 3.63 - 1.60 = 51.39" for the new combo.

Can anyone confirm?

Thanks for your help!

Doug
 
Doug,

Where are you located? I think I may have one of these.

Kern
 
The difference in trans lengths is 3 5/8" but because of the difference in the yokes engaging in the trans between the 904 and 727 the difference in driveline length is 4".

My Duster driveline with 318/833/8 3/4 is 49.25".

49.25" + 3" wheel base difference between the Duster(108") and Dart(111") = 52.25"

52.25" - 4" tranny length difference between the 727 and 833 = 48.25"

48.25" + .66" because of the difference of pinion lengths = 48.9"

48.9" is what looks like your driveline should be center of u-joint to center of u-joint.

I looked at your link and when I compare them to other drivelines on the list some of the measurements don't add up right.

For example: 2660622(66 Valiant) & 2853237(67-76 Dart) drivelines are basically the same length but the difference in wheelbase on both cars is 5". Both cars have the same trans and rearend listed, doesn't add up.

Look at drivelines 2852228/47.81"(67-69 Dart 727/8 3/4) & 2883693/47.99"(70 Dart 727/8 3/4) they are basically what you are going to run except for the rearend. So take those measurements and add .66 because the 8 1/4's pinion is that much shorter than the 8 3/4 and your measurements will be close to what I have calculated.


Chuck
 
Chuck,

The difference in trans lengths is 3 5/8" but because of the difference in the yokes engaging in the trans between the 904 and 727 the difference in driveline length is 4".
Click to expand...

Thanks for the info! Figured that there was more to it than just trans length.


I looked at your link and when I compare them to other drivelines on the list some of the measurements don't add up right.

For example: 2660622(66 Valiant) & 2853237(67-76 Dart) drivelines are basically the same length but the difference in wheelbase on both cars is 5". Both cars have the same trans and rearend listed, doesn't add up.
Click to expand...

I thought the some of the data looked a little fishy on http://www.autohobbydigest.com/table...afts_slip_yoke

Here is another possible complication. It appears that one possible difference between early As and 67 and up is that the wheelbase shifted forward in relation to the firewall. On slantsix.org, DionR was attempting to adapt a later k-frame to an early A.

It appears that when Mopar made the Valiant wider, they also increased the wheel base 2". Most, if not all, of that was done in front of the firewall by moving the front suspension, steering and k-frame forward, while maintaining the same relationship between the motor and firewall. So, in the early A-Bodies, the motor sit farther forward in relation to the k-frame. Thus, my motor mounts are back too far!!!
Click to expand...

(See the following link for details: http://www.slantsix.org/forum/viewt...ays=0&postorder=asc&highlight=kframe&start=15 posted on Tue Nov 28, 2006 12:08 pm by DionR)

If that is true that the wheelbase shifted forward 2" for 67s and up, then the difference between 2853237 (67-76 Dart all engines/904/7.25" rear) = 54.36 vs. 2660607 (66 Dart, all engines/904/7.25" rear) = 56.61 makes some sense.

If I add 2" to your estimate of
48.9" is what looks like your driveline should be center of u-joint to center of u-joint.
Click to expand...
I get 50.9"

Revised Guestimate: 56.61" - 4" - 1.60 = 51.01" for the new combo.

Looks like I'll have to wait and get an actual mock-up measurement to confirm. Please chime in if anyone else has heard of the wheelbase shifting forward in relation to the firewall for 67 and up.

Thanks!

Doug
 
That is interesting on the early to late Valiant wheel base/engine relation stuff, I will look at that being I have both types of cars. I know the early Valiant like my '65 has a wheelbase of 106" and my Duster is 108" so maybe they did get the extra 2" by moving the front wheels forward 2" although I don't think there is a difference in engine set back for two reasons;

(1) U.S. version Darts all had the 111" wheelbase, except Dart wagons (106") and Demon/Dart Sports (108") so if the early k-member thing was right then how come it didn't effect the Darts?

(2) The torsion bars on all A-bodies are the same length. If the wheels were moved forward then the torsion bars and torsion bar cross member would have to move so now the tranny mount would not fit in the crossmember being it would be 2" farther forward but the engine would be in the same place.


You are making the right call to wait and mock up a driveline or if someone here has a '66 Dart with the 727/8 1/4 then they could measure their driveline. My '65 Valiant has a 727/8 3/4 but you would have to add 5.66" due to the 5" wheelbase difference and .66 pinion difference.


Chuck
 
Chuck,

(1) U.S. version Darts all had the 111" wheelbase, except Dart wagons (106") and Demon/Dart Sports (108") so if the early k-member thing was right then how come it didn't effect the Darts?
Click to expand...

I'm assuming (I know that is the way to trouble....) that Darts and Valiants are the same. So if there was a change... it will be with both.

(2) The torsion bars on all A-bodies are the same length. If the wheels were moved forward then the torsion bars and torsion bar cross member would have to move so now the tranny mount would not fit in the crossmember being it would be 2" farther forward but the engine would be in the same place.
Click to expand...

Good Point...IIRC the trans mount also changed in 67. Hmmm....

Tonight I'll measure a 67 Barracuda convertible...it is on the lift right now. I can see what the distance is from the firewall and the trans x-member. I guess another easy reference point would be the upper shock mount and the firewall. That should tell me if there is a difference between each car. No need to crawl under mine for that.

I look forward to solving the drive shaft mystery because that means that I'll have a 340 in my Dart instead of the "on the last leg" slant 6.

Doug
 
Doug,

Wait to have everything in place and take the measurements. Otherwise, you will be in the same boat I was in. I had to get my Keisler driveshaft shortened after my calculations were off because I was inpatient. Plus, I moved the rear back 3/4 of an inch the center the tires in the wheel well. You may want to do this as well because a larger tire will get awfully close to the front wheel lip. Besides, I like symmetry too. Cost me $80 to get shortened so I got off cheap.

Dave
 
Ok..Ok...I wont jump. You've talked me off the ledge.

I "knew" I had to wait...but thought with a little research I could figure an approximate length. I would have thought someone had done this before and could jump in. I guess I was getting too eager.

So within the week I'll know for sure because I'll have an actual measurement. I'll update when I have the drive shaft made.

Doug
 
IIRC the wheelbasr is the same for a 67,8,9 cuda and i used one of those drivesahafts in my car, 360 904, 8.25
 
Revised Guestimate: 56.61" - 4" - 1.60 = 51.01" for the new combo.
Click to expand...

Update - my driveshaft measured out to be 51" for this combo (65 dart, 340/727 with 8.25 rear) It is in the car an fits perfectly.

So there must be something to the idea that the front suspension & trans cross-member shifted forward for the 67 +

Thanks everyone for your input.

Doug
 
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