Moparts
Stock 904 okay behind mild 340?
Posted By: derekeh
Stock 904 okay behind mild 340? - 11/23/09 01:44 PM
The 727 in my cuda is shot so now I need another tranny. I really hate to search for another 727 because I plan on putting a 518 tranny in a couple months. I have a stock 904 that I used behind a 318 for a while. Should it be able to hold up behind a mild 340 or am I wasting my time? 340 is stock 1970 motor with headers and hughes whiplash cam. I have the right driveshaft and everything for this swap so its not too big a deal.
Posted By: JohnRR
Re: Stock 904 okay behind mild 340? - 11/23/09 01:49 PM
As long as you idle around you'll be fine
...
There's a reason the factory didn't put the 904 behind a STOCK 340, which you do not have, even when they finally put it behind a 360 it was a beefed up version.
But go for it and let us know how it works out ...
Posted By: derekeh
Re: Stock 904 okay behind mild 340? - 11/23/09 01:52 PM
Yeah maybe itd be a waste of time
Posted By: joedust451
Re: Stock 904 okay behind mild 340? - 11/23/09 01:55 PM
It should be fine, 904s are alot stronger then some may think, i've tore up a few 727s behind 340s, but in my 360 magnum dart, it'll retain the 904 that came in it, when or if it goes, i'll just just beef it up some, I had a 73 Swinger with a very stout 370 cu. with a built up 904 & Kevlar bands/cheetah VB, it was a killer tranny & laughed at that 370, so if your 904 is in decent shape (even stock), drop it in & don't sweat it.
Posted By: JohnRR
Re: Stock 904 okay behind mild 340? - 11/23/09 01:58 PM
Quote:
Yeah maybe itd be a waste of time
Ifit's only for a short time and you think before you shoot then you could probably still drive it , but if you are going to put it in and beat the snot out of it then , you'll be pulling it back out sooner than you think.
I know on my Dad's 72 duster with the 318 , as soon as I installed headers on it, put in an 8 3/4 with 3.23's and started beating the snot out of it , 17 yr old that just got his license, the 904 didn't last long ... the 7 1/4 took a dump first. Granted I doubt he ever had the fluid changed and the car had about 80k on it when I got my license .
Posted By: derekeh
Re: Stock 904 okay behind mild 340? - 11/23/09 04:13 PM
Yeah im thinking of just putting it in there for now... babying it for the most part lol. Ive always wanted to attempt a transmission rebuild so I might do it on this 727.
Posted By: Dave Watt
Re: Stock 904 okay behind mild 340? - 11/23/09 04:17 PM
I've been running a 904 in my 340 Duster for years without a problem, street and strip.
If a Cuda is like a Duster, the shifter and kickdown linkage is completely different between a 727 and 904.
Posted By: JonC
Re: Stock 904 okay behind mild 340? - 11/23/09 04:17 PM
904 behind mildly built 340 in an Ebody for 15 years now and run hard a lot. Not one problem.
Posted By: derekeh
Re: Stock 904 okay behind mild 340? - 11/23/09 04:24 PM
So the linkage for my slapstick from my 727 wont work?
Posted By: DEMONSIZZLER
Re: Stock 904 okay behind mild 340? - 11/23/09 05:04 PM
Quote:
So the linkage for my slapstick from my 727 wont work?
It will work as long as the 904 has the mounting tabs(two)under the tail shaft for the vertical shifter shaft that goes through the side of the trans tunnel. You will have to use the bracket from the 727 and the rest of the associated shifter parts from the 727 and the drive shaft from the 727 will be too short by about 4".
I actually like the 904 more behind a 340 and have also drag raced with one for about 4 yrs and have driven on the road and no problems. I did modify the valve body to firm up the shifts and exclusively use only type F trans fluid and a brass screen filter. You should be ok and do not expect the trans to hold up to slicks or excessive hi stall launches. If the trans is in good working order, it will hold up, David.
Posted By: Challenger 1
Re: Stock 904 okay behind mild 340? - 11/23/09 05:15 PM
I ran a 904 behind a 340 for years too. It even had nitrous that I would play around with on the street. Tranny had a shift kit installed and it would bark the tires.
Car rusted out, still have the tranny.
I'd install it(904) and see what happens.
Posted By: NachoRT74
Re: Stock 904 okay behind mild 340? - 11/23/09 08:04 PM
and advantage of the 904 is a lighter mass rotation as far I have known...
Of course thats it could be a weak point if we talk about a heavy bracket car, but not on a mild car
Posted By: Paul_Fancsali
Re: Stock 904 okay behind mild 340? - 11/23/09 08:37 PM
Put it in a heavy B body and see the trans come apart. I have used them 3 in my 73 and never again! However they are good for close to .15 in the qtr ove a 727. A good 727 in a heavy car is worth the extra money and slower times
Posted By: RapidRobert
Re: Stock 904 okay behind mild 340? - 11/23/09 09:18 PM
Quote:
Should it be able to hold up behind a mild 340. I have the right driveshaft and everything for this swap so its not too big a deal.
(1) yes (2) your all set
Posted By: Anonymous
Re: Stock 904 okay behind mild 340? - 11/23/09 10:23 PM
yup. 904's in heavy cars with some power not a good idea. unless you like shredded floorboards
and your girlfriend beating on you saying [Edited by Moparts - Family Friendly Site - Keep it clean]..
Posted By: 70AARcuda
Re: Stock 904 okay behind mild 340? - 11/24/09 12:28 AM
Quote:
yup. 904's in heavy cars with some power not a good idea. unless you like shredded floorboards
and your girlfriend beating on you saying [Edited by Moparts - Family Friendly Site - Keep it clean]..
have yet to see a 904 come apart like a 727 ...been drag racing with the same 904 for 15 yrs. it has been rebuilt once in that time frame...because ring gear broke and took out rear spraq...and i have been using a trans brake on that 904 for 15 yrs...
see 69 barracuda in signature
71 dart in signature has 904 with transbrake with 3 seasons on it..
and these are 904 with aluminum plantaires...not the 999 steel one...
and i rebuilt both of them...and i am no expert.
Posted By: 69L78Nova
Re: Stock 904 okay behind mild 340? - 11/24/09 12:56 AM
I ran 10.80s in a 63 Dart for 7 years with a 360 and a 904. Never had one problem with it
Posted By: Wedgeman
Re: Stock 904 okay behind mild 340? - 11/24/09 01:02 AM
So I would expect my 999 to hold up behind my stroked 5.9l magnum anytime ?
Any mods needed as insurrance ?
Dan
Posted By: Anonymous
Re: Stock 904 okay behind mild 340? - 11/24/09 01:32 AM
Quote:
Quote:
yup. 904's in heavy cars with some power not a good idea. unless you like shredded floorboards
and your girlfriend beating on you saying [Edited by Moparts - Family Friendly Site - Keep it clean]..
have yet to see a 904 come apart like a 727 ...been drag racing with the same 904 for 15 yrs. it has been rebuilt once in that time frame...because ring gear broke and took out rear spraq...and i have been using a trans brake on that 904 for 15 yrs...
see 69 barracuda in signature
71 dart in signature has 904 with transbrake with 3 seasons on it..
and these are 904 with aluminum plantaires...not the 999 steel one...
and i rebuilt both of them...and i am no expert.
HEAVY cars. lets here how many people use stock or the usual hop-ups 904 trannys in
say a 71 roadrunner, or a 68 charger. with a 300hp/340cid or better engine..
like already stated above. theres a reason why MoPar never put those in there
performance lineup.
Darts and A-body barracudas depite what you may think, are not heavy cars.
Posted By: Lil Wedge
Re: Stock 904 okay behind mild 340? - 11/24/09 03:09 AM
I run 904's in both cars, the Cuda weighs 3700 lb, runs mid 11's(10.80 best)1.40 60' same trans since 02, The Dart is 3000 lb. Transbrake best of 9.80's 1.27 60' time, usually lasts whole season, nothin fancy in either, deep pan and manual valve body. Only broke one once(output shaft).
Posted By: Lil Wedge
Re: Stock 904 okay behind mild 340? - 11/24/09 03:11 AM
The Cuda with 360 and 904
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Posted By: derekeh
Re: Stock 904 okay behind mild 340? - 11/24/09 03:24 AM
My 904 is stock though.. dont think its going to hold up to a wheel stander lol.
Posted By: Lil Wedge
Re: Stock 904 okay behind mild 340? - 11/24/09 03:36 AM
Mine is too!! Only thing I do different is a better clutch and steels. I have run stock clutches before, no problems, They work, Only way your 340 will hurt that trans is if the trans is already worn out. The Wheelstand pic was to show you what they will take and keep on going. Besides you will pick some power going from 727 to 904, usually 1-2 tenths in 1/4 mile, like a free 20-25 horsepower gain !!
Posted By: Wedgeman
Re: Stock 904 okay behind mild 340? - 11/24/09 10:40 PM
I contacted SMR transmissions and the have simple
mods to have a killer 904 !
They only work on Mopar transmissions and torques
Dan
Posted By: DaytonaTurbo
Re: Stock 904 okay behind mild 340? - 11/24/09 10:46 PM
If you're that concerned, just put the 904 in and run it easy until you've got the new 518 or 727 ready. Then start beating on it and make an honest attempt to kill it just to see if you succeed!
Posted By: Wedgeman
Re: Stock 904 okay behind mild 340? - 11/24/09 10:47 PM
To go where you haven't gone before ? GREAT IDEA !!
Posted By: 5thAve
Re: Stock 904 okay behind mild 340? - 11/25/09 01:19 AM
Stick with a 727. It sounds like you'll need some different parts anyway to use a 904 and you'll definately need a different driveshaft so even if you're planning on changing to a 518 soon anyway it would be easier to just get another 727 to use in the meantime.
Posted By: derekeh
Re: Stock 904 okay behind mild 340? - 11/25/09 04:18 AM
I have everything for the 904 swap since I had a 904 behind a mild 318 a while back so thats no issue.
Posted By: 69L78Nova
Re: Stock 904 okay behind mild 340? - 11/25/09 04:56 AM
Youll be fine. There isnt anything magical about a 340. It doesnt take much at all to get the power of a 318 to stock 340 ratings
Posted By: joedust451
Re: Stock 904 okay behind mild 340? - 11/25/09 05:25 AM
Like i said earlier, drop in the 904 if you have everything, most that say don't run the 904 don't really know how much they will take, & don't give them the benifit of a doubt, to me, its the little brother to the 727, & deserves its right to be trusted as a stout little tranny that it "TRUELY" is!!
Just think of it as is what a TH350 is to the chevy crowd, those are some damn good trannies when built too. I really like the 904 personally.
The "only" reason chrysler installed 727s behind most 340/360 A bodies was, most people were going to thrash on those cars, & they knew even the stock 727 would hold up for warranty purposes (smart thinking), but that doesn't mean the 904 was a wimp, especially when beefed up.
Posted By: RapidRobert
Re: Stock 904 okay behind mild 340? - 11/25/09 05:29 AM
Quote:
Like i said earlier, drop in the 904 if you have everything, most that say don't run the 904 don't really know how much they will take, & don't give them the benifit of a doubt, to me, its the little brother to the 727, & deserves its right to be trusted as a stout little tranny that is "TRUELY" is!!
& I'm even putting one (w a jw ultrabell adapter) behind my 451 going into a 65 dart 
Posted By: Runner2go
Re: Stock 904 okay behind mild 340? - 11/25/09 05:49 AM
360 in my Challenger with a 904 behind it.
Ran mid 12's on tires and put about 30k miles on it without an issue.
Plan to continue to use it when the car comes back out of storage in a year or two.
Posted By: denfireguy
Re: Stock 904 okay behind mild 340? - 11/25/09 05:01 PM
No one has mentioned the biggest advantage I have seen with the 904/A500: Lower first gear ratio. With street/stock rear ratios, that lower first gear will take you off the line much faster.
Rebuild a 904 with Kolene steels and Raybestos frictions or the equivilent and it will, IMHO, last just as long as a 727.
Volare cop cars with the 904 did just fine with many fleet operations (city of Aurora, CO for one) putting in shift kits to firm up the sloppy shifting and adding life to the transmission. If anyone can kill a transmission, cops can.
Craig
Posted By: joedust451
Re: Stock 904 okay behind mild 340? - 11/25/09 07:21 PM
Is there any decent low cost shift kits out there for the 904?
Posted By: Wedgeman
Re: Stock 904 okay behind mild 340? - 11/25/09 09:45 PM
Is 275 ok ?
Posted By: 5thAve
Re: Stock 904 okay behind mild 340? - 11/25/09 11:58 PM
Quote:
Like i said earlier, drop in the 904 if you have everything, most that say don't run the 904 don't really know how much they will take, & don't give them the benifit of a doubt, to me, its the little brother to the 727, & deserves its right to be trusted as a stout little tranny that it "TRUELY" is!!
Just think of it as is what a TH350 is to the chevy crowd, those are some damn good trannies when built too. I really like the 904 personally.
The "only" reason chrysler installed 727s behind most 340/360 A bodies was, most people were going to thrash on those cars, & they knew even the stock 727 would hold up for warranty purposes (smart thinking), but that doesn't mean the 904 was a wimp, especially when beefed up.
A lot of people who say not to use them say it because of been there done that broke it. It really just depends on what car you have and how you're using it.
Posted By: derekeh
Re: Stock 904 okay behind mild 340? - 11/26/09 02:37 AM
Well I put the 904 and have it all running.. we will see how well it does lol.
Posted By: Mike H
Re: Stock 904 okay behind mild 340? - 11/26/09 03:12 AM
So what would you guys do if you had a 904 out of the car, and it was only going to have a stout 360 in front of it? What would change if anything?