904 to 727 Swap

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CamaroHunter

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I am working on my first Mopar build a 1967 dart for my son and do not have a lot of knowledge on what parts interchange. I am going through everything since the car has been sitting a long time. The car currently has an A-904 in it but I have a opportunity to purchase a small block A-727 that has already been rebuilt for a good price. The engine is a 1970 340 making around 400hp. I am just not sure if I will have to change a bunch of stuff that might not make it worth the money saved.
I appreciate any info I can get.

Thanks
 
You will need a different driveshaft and yoke, as the 727 tail is longer and different splines.

It will bolt right up and sit in the car, same rear mount

Kickdown linkage MAY (probly is) different

(Mine is manual valve so I don't use kickdown)

If you have a console shifter, make sure the new trans has the mounting holes for the bottom shifter bracket, not all do
 
That's what i needed to know. I have not really looked at the transmission in the car yet. i just talked to this guy today. I can get the transmission and 3500 rpm stall converter for $450.00. It has around 2800 miles on it since it was rebuilt. Should the one I am looking to purchase have a certain number of holes or configuration for the linkage? Can I put the correct yoke on the drive shaft and have it shortened or is more cost effective to just buy a new drive shaft?

Thanks again.
 
Why change the 904? Easy rebuild and you're good to go without having to dick around with changing the yoke and cutting down the driveshaft for the 727.
 
CamaroHunter said:
Should the one I am looking to purchase have a certain number of holes or configuration for the linkage?

Can I put the correct yoke on the drive shaft and have it shortened or is more cost effective to just buy a new drive shaft?

Thanks again.
Click to expand...

Yes. the bottom bracket for the stock shifter bolts to the bottom of the transmisison tail housing. In the photo below, you can see the two holes on the bottom of the tail right behind the pan This of course only applies to factory console shifters

727.jpg


I would keep the driveshaft as is--you MIGHT want to put the 904 back in some day. You could find a junk B shaft and have it shortened
 
how about going from a 727 to a A833 on a 'A' body with a 8 3/4. would i need a new drive shaft and yoke'? or same relative length?
 
Thanks for all of the replies. It is great to have someplace to ask questions when needed and sorry for not responding sooner. I have not been in front of a computer for a few days. To answer the last question from thesiren74 it is a original 273 two barrel car that has been sitting since since 1997. Since I am replacing the motor I had a chance to get a rebuilt A-727 a lot cheaper than paying to have the A-904 rebuilt.
 
The 904 is easy to rebuild. I did mine with zero transmission experience and it went just fine. They're very simple bits of machine.
 
BIG-B-Barracuda said:
how about going from a 727 to a A833 on a 'A' body with a 8 3/4. would i need a new drive shaft and yoke'? or same relative length?
Click to expand...

The A-body, short tailshaft A833 and the 904 are the same length. The 727 is 4" longer. The yoke on most 833's is the same as on the 727 (some of the 833OD's used the 904 yoke).

So, you would need a new driveshaft, because the one for the 833 will need to be 4" longer.
 
Corrupt_Reverend said:
The 904 is easy to rebuild. I did mine with zero transmission experience and it went just fine. They're very simple bits of machine.
Click to expand...

You can say that again, a blind man could rebuild one. Plus they take 20HP less to spin.

Don't be shy get in there!!!
 
The dude has said more than once he wants the 727 and why. Lay the F off already. He'll never feel the difference between the two transmissions. Might see it on a time slip or on the dyno. Damn yall are hard headed. Just answer dude's questions.
 
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