904 to 727 conversion crossmember

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70-duster

70-duster

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is there a difference in the transmission crossmember on a 70 duster when doing this swap? I currently have a 1974 904 and I'm swapping in a 1968 727. I already know I have to get a new converter and have the driveshaft shortened.
 
abodyjoe said:
crossmember is the same for both. so is the trans mount.

why the swap? 904 is a better way to go.
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I blew up my 904. I called a good trans builder and he said, along with some other mopar buddies, that I'd be better off running a 727 behind my built 340. The trans builder told me he would bulletproof the 727. He said it was a stronger trans. I heard both stories about the 904 and the 727, not sure which to believe anymore
 
Oh brother. That's one trans man I wouldn't trust and apparently your mopar buddies aren't very knowledgeable either.
 
abodyjoe said:
Oh brother. That's one trans man I wouldn't trust and apparently your mopar buddies aren't very knowledgeable either.
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So tell me why I should build a 904 vs a 727? 727 looks more heavy duty than a 904, the input shaft is even so much bigger.
 
Why would they put a 727 behind the 340 cars and not the 904 back in the 70's? This 904 was behind a grandma 318.
 
Lighter, faster and cheaper since you don't need to shorten your driveshaft.

904 can be built to withstand a lot of power with out any exotic parts. Just quality parts and someone who knows how to build them.
 
70-duster said:
Why would they put a 727 behind the 340 cars and not the 904 back in the 70's? This 904 was behind a grandma 318.
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Because it was 1970. Things and materials have changed a lot in 47 years.

Your buddies and trans guy sound like the type that will also tell you that you can't or shouldn't use a converter that's over a 3000 stall on the street too. Totally wrong also.
 
Hey it's your time and money. If you want to put that heavy *** power robbing 727 in your car that's all you.

Me. All my small block cars get a 904. The one in out dart now I had done in 2005. Beat the everliving shot out of that trans for 10 years and it never skipped s beat. Only reason I had it freshened up is because I had it out to put it in this car (was in my yellow dart all those years). My buddy opened it and said you could have just thrown it in ya know. I figured for a few hundred I may as well have the trans fresh like the motor and everything else on the car. :)
 
Ok, if your just doing the typical "300 dollar bench job" rebuild at your local tranny shop, then yes, the 727 is much tougher.
In other words, just rebuilding them both to stock specs, the 727 is much tougher. However, IF you are willing to upgrade some components in the 904, it will hold up to some big horsepower motors. Many of racers run 904's with great success.
  • 904 is lighter, with lighter rotating components. this makes it about 3 tenths faster, and a hair better on gas. It also is smaller, giving more room.
 
727 is tougher but takes more HP
a well built 904 will be fairly tough but is better for racing. Most people here push 904's due to this.

Me, personally, it's just a driver so I went with a 727.
 
abodyjoe said:
Because it was 1970. Things and materials have changed a lot in 47 years.

Your buddies and trans guy sound like the type that will also tell you that you can't or shouldn't use a converter that's over a 3000 stall on the street too. Totally wrong also.
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So lighter would be better in a drag car, which it's not. Faster, that all depends on a lot of other things other than the transmission and again it's not a drag car. And then there's cheaper, isn't there a saying you get what you pay for? I'm not about cheap, I'm about stronger and handling the power. Thanks for your input, but insulting the people I know doesn't make me want to listen to you.
 
Then don't Listen. No sweat off my ***.


It's cheaper only because you Already have the drive shaft for the 904.
 
a 904 is about an inch narrower than a 727 so the torque shaft for your shifter will be too long if you use the 727.It also has a lower mount.You can force your 904 piece in sometimes and although it's crooked and binds sometimes they work but aren't correct.Sounds like you are determined to use the 727 so you should shorten the shaft about an inch and fanagle the trans. bracket lower.
i also use a 904 behind my 340
 
kiss said:
727 is tougher but takes more HP
a well built 904 will be fairly tough but is better for racing. Most people here push 904's due to this.

Me, personally, it's just a driver so I went with a 727.
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My cars pushing 425hp.
 
425 hp is nothing for a 904 built by someone who knows what they are doing.. again nothing exotic is needed. just quality parts nd a person that know what they are doing.
 
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