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727 Transmission questions #2675375
07/07/19 10:27 PM
07/07/19 10:27 PM
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440mopar Offline OP
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I have some questions about 727 transmissions.

First, are all small block 727's the same? I know big block 727's vary depending on the engine they were used on but I've never read anything on small block 727's having any variations. I have one from a 69 340 Barracuda and also one from a 72 340 Challenger. Just wondering if one is better than the other as I would like to keep one and sell one.

Second, I have a 318/904 combo presently in one of my cars that I plan on putting a 340 in. The 340 isn't stroked or anything radical, just T/A heads, a little bigger than stock cam, bigger carb and headers. Is there any reason to not leave the 904 in the car or should I put a 727 behind the 340?

Third, would there be any reason to chose one of the following big block 727's over the others to have built to run with a 400/470 stroker motor (street car, not race)? I have three to choose from, one from a 69 Road Runner, one from a 70 full size Chrysler with a 440 and one from a 72 Road Runner with a 400.

Re: 727 Transmission questions [Re: 440mopar] #2675405
07/08/19 12:20 AM
07/08/19 12:20 AM
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Freeport IL USA
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poorboy Offline
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When it comes to 727s, any year newer then a 71 gets my vote. In 71 Mopar installed the part throttle kick down. Its hands up better then the older trans with the full throttle kick down.

As far as the 904 behind a 340, I beat on one pretty heavily that was installed in a 69 Charger for more then a year. Then someone wanted that Charger a whole lot more then I did, and I sent it away. Have no idea how long the 904, or the 340 lasted after it left my possession. Gene

Re: 727 Transmission questions [Re: 440mopar] #2675407
07/08/19 12:26 AM
07/08/19 12:26 AM
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dogdays Offline
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I don't think smallblock 727s are the same but my Chassis book is buried so someone else will have to reply.
The 904 transmissions were different for different engines.The one I'd pick for your car was behind the high perf 360s, the A999, IIRC. It had the most clutches and would definitely hold up to the 340 you have outlined. In case you don't know, the 727 eats more power than the 904 variants. Plus you can get the 998 or 999 with a 2.74 First gear which I'd pick because it'd allow use of one step lower (numerically) gear in the rear and leave the line the same.

For bigblocks I'd pick whatever Transman told me to do.
R.

Re: 727 Transmission questions [Re: 440mopar] #2675574
07/08/19 02:22 PM
07/08/19 02:22 PM
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John_Kunkel Offline
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The internals of BB and SB 727's and 904's vary with the engine power, any of the 727's listed would be a good core to build with the '72 being first on the list.

A 904 from an early 318 might be marginal with a built 340 but a later 998 or 999 would be just fine.


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Re: 727 Transmission questions [Re: John_Kunkel] #2675665
07/08/19 06:07 PM
07/08/19 06:07 PM
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Every time I do swaps like that but usually from a 318 to 360 if the 904 is still good I run it till it dies and then go to a 727. I've never had one last more then a year. They last a bit longer if they've been freshened up.

Re: 727 Transmission questions [Re: John_Kunkel] #2676141
07/10/19 12:55 AM
07/10/19 12:55 AM
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Aurora, Colorado
451Mopar Offline
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Originally Posted by John_Kunkel
The internals of BB and SB 727's and 904's vary with the engine power, any of the 727's listed would be a good core to build with the '72 being first on the list.

A 904 from an early 318 might be marginal with a built 340 but a later 998 or 999 would be just fine.


With the torqueflight transmissions, there are a few differences like John mentioned above. Any can be built to the same level by changing out some parts.
With the 727, any of the '67 and up are a decent choice, before that the input shaft, converter, front pump are different, and pre-66 have the rear pump and cable shift.
Most high performance 727s use the 1971-up front pump and drum with the wider drum bushing. Some have a drum with the retainer clip machined for 3 clutches, where the high performance cars have a drum that accepts 4 clutches.
There was also the 5 clutch Hemi drum. In most applications the 3 clutch unit will be fine. I ran a stock 4 clutch unit in my 12 second 4,100 lb Charger for years. The front aluminum gear splines did look like they were on their way out when I re-built it for the new engine. The 904 is also good if built correctly and it takes less power to run. With any transmission, proper assembly, a trans-go shift kit, and a trans cooler go a long way in making sure they last a long time.

Re: 727 Transmission questions [Re: 451Mopar] #2676719
07/12/19 07:09 AM
07/12/19 07:09 AM
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440mopar Offline OP
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OK, thanks guys. I guess I will keep the 72 small block 727 and use the 72 big block 727 from the Road Runner for my 470. I wanted to know which were the best to use/keep so I can get rid of the rest of them as I really need to free up some space in my garage.







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