Tranny Swap questions

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CUDACOX

CUDACOX

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Hi all, I'm wanting to switch trannys from 727 to my factory 904.I will get the 904 rebuilt with all good parts of course.My questions are...What linkages will I need?And..Has anyone done this and noticed a difference? better? worse? same?I know the 904 is about 50-60 pounds lighter than the 727.I will also get the stock 904 converter rebuilt. Thanks in advance!:salute:
 
What your reasoning for changing If I may inquire,you would need to get a longer driveshaft,and yoke,think everything else is a wash pretty much,the 727 is tougher better trans in my opinion,is this an everyday driver or something else?
 
Console shift/318 in 68 cuda right Craig? Ive heard different things on here about 904 vs 727. I will chk my parts manuals
 
4spdragtop said:
Console shift/318 in 68 cuda right Craig? Ive heard different things on here about 904 vs 727. I will chk my parts manuals
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Correct. Thanks Steve. Warmed over 340,3:55 sure grip.Drive shaft I know will need changing. I have heard the 904 is a great tuff tranny also.
 
The 904 is a great trans :coffee2: they have been used in light duty trucks and can be built to handle up to at least 400 hp and I have seen even more.
In 2002 the fastest street car was a 71 dart and ran in the 10's with a 904 trans here in the door slammer shoot out here in the southeast shoot out Memphis Motor Sports Park, yes I was there ..:burnout:
 
Craig, I don't have 1st hand knowledge, BUT I remember helping Ed/Nitemoves and it was a bit of a guessing game, not knowing where some of the parts came from.
I checked my parts manuals and I see NO different parts listed in your case from 904 vs 727.
Pettybludart runs a 904 in has race car with NO issues. But his aint stock by any means either.
 
4spdragtop said:
Craig, I don't have 1st hand knowledge, BUT I remember helping Ed/Nitemoves and it was a bit of a guessing game, not knowing where some of the parts came from.
I checked my parts manuals and I see NO different parts listed in your case from 904 vs 727.
Pettybludart runs a 904 in has race car with NO issues. But his aint stock by any means either.
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Yes, Steve is right.

We've had a 72 Ralley Challenger in the family for years. My brother bought it in high school, then I bought it from him so he could buy a 69 Roadrunner. Then I sold it back to him, and now it belongs to my oldest son.

It was originally a 318 car. I drove it with a 70 340 and a 727 trans. We NEVER changed the linkages from one trans to the other, they are completely interchangeable.

I also changed the engine in my 67 Formula S 273/904 to a 340 with a 727, also using the same trans linkages with a console. I also changed my first 68 Barracuda 318 car (column shift) to a 727 and the original linkages also worked on both transmissions.

In addition to being lighter, I believe that the 904 has a lower 1st gear ratio so you should be a little faster in first gear than with the 727.

Yes, you will have to get your driveshaft "adjusted" as the 727 is about 2" longer than the 904.


I've heard of drag racers using 904's instead of 727's. If you rebuild them with heavy duty parts, they will hold together and with them being lighter and the better 1st gear ratio, get a better 1/4 mile time.



When I first saw the title for this thread, I thought that this should be in the "blue forum"... LOL!
 
And there's the fact that the 904 uses about 35 hp less than the 727.
 
904s CAN run, racers like them because they are lighter as well. Ill be having the one in my 71 rebuilt when the time comes.
 
are you running a column shift or a console? Finding the shifter linkages for a 904 column is pretty easy. Finding a 727 to column is the tough part. My valiant had a 904 and someone swapped it to a 727 and it doesn't shift very smooth because the linkages and shafts don't line up very well.

Check out Ididit's column linkage (if that's the route you're going). It's available through Summit Racing.

If it's kick down linkages your after, they are available through year one I believe.
 
roylerumble said:
are you running a column shift or a console? Finding the shifter linkages for a 904 column is pretty easy. Finding a 727 to column is the tough part. My valiant had a 904 and someone swapped it to a 727 and it doesn't shift very smooth because the linkages and shafts don't line up very well.

Check out Ididit's column linkage (if that's the route you're going). It's available through Summit Racing.

If it's kick down linkages your after, they are available through year one I believe.
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Right now I have factory console with a earmed over 340/727.Just wondering also what anyone would suggest for stall speed.
 
CUDACOX said:
Right now I have factory console with a earmed over 340/727.Just wondering also what anyone would suggest for stall speed.
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Would need to know approxomate power output, rear gears and tire size to recommend that.
Probably best to ask a manufacturer anyway.
 
Hi Craig I did this same swap in my fastback after the pro built 727 started slipping and using fluid the first year I came to Moparfest , The Kickdown linkage will change geometry a little but nothing major , I was told there are 2 different shift length levers that connect at the trans itself but mine were the same on both so I just had to fiddle with adjustment on that one , You will also need to figure out yokes and ujoints but all in all you will be glad you got rid of the 727 , call the guys at TCS Products in Langly BC they will set you up right , as for the convertor go as low as you can for street use the be honest with them about tyhe use of the car and the set up and they will know what you need , mine is stalled to high for what I use the car and that just wastes fuel and money , a free restall is on the menu .
 
cannucky said:
Hi Craig I did this same swap in my fastback after the pro built 727 started slipping and using fluid the first year I came to Moparfest , The Kickdown linkage will change geometry a little but nothing major , I was told there are 2 different shift length levers that connect at the trans itself but mine were the same on both so I just had to fiddle with adjustment on that one , You will also need to figure out yokes and ujoints but all in all you will be glad you got rid of the 727 , call the guys at TCS Products in Langly BC they will set you up right , as for the convertor go as low as you can for street use the be honest with them about tyhe use of the car and the set up and they will know what you need , mine is stalled to high for what I use the car and that just wastes fuel and money , a free restall is on the menu .
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Thanks Buddy!
 
CUDACOX said:
Anyone else do the swap?
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Check out www.tcsproducts.com.
Owners race car BA/A, 500 cu. in Steve Schmidt Pro-Stock GM engine (about 1200hp). Used to work there, and to the best of my knowledge running a 904 behind the engine. Car runs high 6's, 200+Mph. Was the BA/A NHRA record holder at one time.
You can on their website go to the specification page, and have them spec. out a converter for you.
Guys to talk there on the 1-800-960-1177 line either Paul or Steve.

have fun
 
CUDACOX said:
The 35 less HP factor? Where is this info? I'm interested in reading! Thanks.
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Sorry, in looking it up it seems that the 904 uses more like 20 hp less than the 727.
I can find a lot of info on it, but nothing official other than some comparison charts.
 
it's tough to judge the difference that way because in a stock application the numbers were calculated as a percentage but of course drive train part changes change the amount needed to turn it and hp changes likewise affect the percentage , It's the difference in the diameter of the drums and the amount of rotational mass that makes them more efficient and safer than a 727 .
 
send your converter to "Converterman" in the city.
he'll want your car,build and cam specs and he'll
build a converter that will stall for your max torque rpm
..don't rely on someones guess.
 
TrailBeast said:
And there's the fact that the 904 uses about 35 hp less than the 727.
Click to expand...

That may be a myth. If you equip the same drag car ..one with a 904 and the other with a 727 , the end time difference is under a qtr of a second.

Building up a tuff 904 is (what I gather on this board ) is more expensive.. as well with the converter..

They both blow up if abused.. but most antidotal info on this site re these trans is from drag racing and I am not sure how many of us hobby drivers thrash our cars that hard.

the 904 is lighter but with all the hp our cars are making, will we notice it ? And ma Chrysler , in some cases, mated the /6 with the 727..

Regardless, the arguments tend to get religious..like Mac vs IBM..

Not sure why buddy wants to swap out a perfectly working 727 with another trans..

One of the best (if not the best) transmission shops in our province is owned by a fairly serious mopar dude... he runs a 727 in his car too...

No matter, my opinion :)

Grassy
 
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