/6 to V8 swap

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Madhatter1776

Madhatter1776

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Ok not sure if this is the right section but here it goes, I am swapping my 1975 Duster /6 engine, trans and rear axle. I had the old 7/14 rear axle and 904 trans, I now have an 8 3/4 rear axle set up, and a V/8 904. I am swapping the /6 k member to the V/8 K member, dont have everything mocked up yet as I am in the process, was wondering if I am going to need to swap the drive shaft? Also do I need to swap the torsion keys when switching to the V/8 bars, also what is the diff between the V8 /6 bars?
Thanks
Bryan
 
You will need a different drive shaft and the slant 6 t- bars will work but might be better to swap in some bigger bars now if you want to do it right the first time.
 
shanson30 said:
You will need a different drive shaft and the slant 6 t- bars will work but might be better to swap in some bigger bars now if you want to do it right the first time.
Click to expand...

Agree. /6 bars are smaller diameter between the Hex ends. All "A" body Hex and length is the same.
 
The 8 3/4 axle is about 2" longer than the 7 1/4 axle, the driveshaft will have to be shortened.

Also, FYI, a 727 is also about 2" longer than a 904 and will need the driveshaft to be shortened also. (In case you consider it for the future).

You may want to consider the 1" torsion bars from Just Suspension or the 1.030" torsion bars from PST if you want better handling. Many guys who have swapped to these are happy with them and they are not too stiff.
 
Ok The reason I ask about the T-bars is when I bought the car, I was told it they had once swapped the engine, I bought the v8 k-member w/t-bars, pulled the suspension, and the bars are identical, so how do I know if they are right, here is my attempt at some pics of what I got
 

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Ok on one both sides say 891L and one side also has a 255, then the other says clz.
The second one has 890 then cbw, then on the opposite side say 117 then a symbol or something I cant make out
 
Madhatter1776 said:
Ok not sure if this is the right section but here it goes, I am swapping my 1975 Duster /6 engine, trans and rear axle. I had the old 7/14 rear axle and 904 trans, I now have an 8 3/4 rear axle set up, and a V/8 904. I am swapping the /6 k member to the V/8 K member, dont have everything mocked up yet as I am in the process, was wondering if I am going to need to swap the drive shaft?
Click to expand...
No. If swapping same trans to same wheel base, it's not necessary. The 904 has the same length tail shaft, unless it is used w/4wd, and it attaches to the cross member at the same point regardless of /6 or V8.
Madhatter1776 said:
Also do I need to swap the torsion keys when switching to the V/8 bars,
Click to expand...
Keys?
Madhatter1776 said:
also what is the diff between the V8 /6 bars?
Click to expand...
Diameter. IIRC the 225 w/ A/C used the same bars as the 318 w/o A/C. The 318 w/ A/C & the 340 used the same bar, .870, all 383 cars used the .890 bar. The 225 bars work fine, but very good HD gas shock needs to be used with them. FWIW, when I converted the Demon, I used a '75 K-frame w/sway bar, 1.0 T-bars, and Monroe Gasmatic shocks. Works like a champ.
Madhatter1776 said:
Thanks
Bryan
Click to expand...
 
Did you swap k members yet. I used the Schumaker adapters and they worked fine. What year the 8 3/4 out of? Does it have the bigger rear drums on it?
Pick up a manual and through a rebuild kit and shift kit in the 904 while you got it out. They are not that hard.
 
Madhatter1776 said:
Ok on one both sides say 891L and one side also has a 255, then the other says clz.
The second one has 890 then cbw, then on the opposite side say 117 then a symbol or something I cant make out
Click to expand...

The part numbers you listed breakout to part number 2535890 and 2535891
891L (left side)
890R (right side)
These are .850 in diameter and were installed on /6 with air or 318 without air.
 
Ok So if I am reading right, I am putting a 360 in, I have T-bars that will work with better shocks, or I should get the 1inch T-bars, my drive shaft should work as the 904 I am using came out of an 80 something Imperial with a 318, worst case I will have to shorten it some, As far as the keys go, I was talking about the bolt deal int the lower control arm. The axle is off of a 69 dart, I have already swapped shafts and such, now using 10 inch drums, the /6 K-member is out and I am ready to swap, The T-bar threw me as I was expecting to see something different between the sets I have. Now that makes sense on why they are the same, My car had the /6 w/ac, the t-bar I got were from a 318/ w no air. I do not plan on putting A/C in my car.
 
Everything sounds OK to me. As far as the T-bars go, it depends in the final analysis what you plan to do with the car. If it's to be a tire frier with an occasional ¼ mile, what you have will be OK. If you want a canyon carver, IMHO, you'll want a larger T-bar as well as an anti-roll bar on the front end. Good luck and happy motoring.
 
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