904 vs. 727

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70-duster

70-duster

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I currently have a 904 transmission in my 70 duster. It needs arebuild. I also have another 904 that has 36,000 miles on it. Here is my dilema, I just bought a 360 v8 and a 727 that was behind it. It was recently rebuilt and only has about 200 miles on it. I am going to put this 360 in the duster. The 360 was rebuilt 5000 miles ago. It was a stock rebuild other than it being bored 0.30. I may put a larger cam in it before it goes in the car. I will be running an 8.25 rear with highway gears. The duster will be used for cruises and shows. Should I put this low mileage 904 trans in it and just sell the 727, or use the 727?
 
I put the 904 in my 65 Barracuda Formula S. I was told if you change to a 727 you will have to find a new drive shaft. The transmissions are a different length. Another plus was the folks that built my 904 said it was lighter than the 727.
Maybe someone else will chime in, but this was the info I had.
 
IMO you'd be better off with the 904 because they consume less hp to operate and is plenty strong for a mild 360 but this low mileage unit you have is how old? Mileage means very little when it comes to seals. They dry out and get rock hard over time so they don't seal well. If I were going to use it I'd pull it apart and reseal it. You can always sell the 727 and use the money you get to help pay for parts to reseal the 904.
 
70-duster said:
I currently have a 904 transmission in my 70 duster. It needs arebuild. I also have another 904 that has 36,000 miles on it. Here is my dilema, I just bought a 360 v8 and a 727 that was behind it. It was recently rebuilt and only has about 200 miles on it. I am going to put this 360 in the duster. The 360 was rebuilt 5000 miles ago. It was a stock rebuild other than it being bored 0.30. I may put a larger cam in it before it goes in the car. I will be running an 8.25 rear with highway gears. The duster will be used for cruises and shows. Should I put this low mileage 904 trans in it and just sell the 727, or use the 727?
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The word on the street is that a 904 is about 1 to-1-and-a-half carlengths quicker than a 727 in the same car/same engine in the quarter-mile. Talking small block A-Bodies, in that instance.

Important, if you drag race... Maybe not, if you don't.

That's the main reason to use a 904; they don't sap as much (parasitic) horsepower because the rotating internals are lighter.

The 904 seems capable of handling up to at least 600 horsepower, if built with the right parts.

MOST small blocks don't exceed that, so it's the transmission of choice for many.
 
the 904 is the racers choice for reasons stated. 904 can handle the 360 depending on the power level you plan to put out with your 360. i have put 350 hp against a stock 904 with a good shift kit and it handled it no problem.the 904 can be modified no problem to handle very high power levels also. the 727 out of the box is a brute. very few things need to be done to handle most things you throw at it. there is a short er version of the 727. if you have that one you wont need a shorter shaft i believe but you will need to change the slip yoke to the 727 size. cutting the drive shaft on the other hand is not that big of a deal. if you just want a rebuilt trans and the 727 is recent rebuilt then that not a bad idea but if you don't have the short version it will cost you some. the 904 can be rebuilt for not a hole lot. there is a guy local here that will do them for 350-400 dollars check your area. if its a money thing you need to deiced if it isn't i say stay with the 904. with what your planning on doing
 
I would say go with the 904. TQ hubs like to crack and spoo ATF all over the place so look at that vary close.
Don't bind it up when installing the transmission, aka make sure it all the way in the transmission before install
 
Thank you guys for your input. I will be listing the 727 for sale along with an extra 904. I actually have 2 904's, so if anyone is interested in either trans, shoot me an offer.
 
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