904 to 727

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n00blike

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I have a 74 duster with a 360 and 904 I may be going from a 904 to a 727. What modifications would i need to do? is a 727 that much better then a 904?
 
You will need to shorten your driveline 4" and change the front yoke. The tranny mount and crossmember are the same.


Chuck
 
If you don't mind my asking, why are you switching to a 727? Are you putting some serious power down? Racing?

A well-built 904 is an awesome transmission for a small block dude, and they're more capable than people think. A 904 has a lighter rotating weight than a 727 and even shifts slightly quicker. Get a bolt in sprag to toughen it up. You might find out that a 727 did nothing more than add weight in the long run.

IMHO keep your 904 if its a street car. As long as you have it built right it will suit your 360 just fine.
 
YoungBlood said:
If you don't mind my asking, why are you switching to a 727? Are you putting some serious power down? Racing?

A well-built 904 is an awesome transmission for a small block dude, and they're more capable than people think. A 904 has a lighter rotating weight than a 727 and even shifts slightly quicker. Get a bolt in sprag to toughen it up. You might find out that a 727 did nothing more than add weight in the long run.

IMHO keep your 904 if its a street car. As long as you have it built right it will suit your 360 just fine.
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exactly, go for a 904, less power to rotate and can handle the power when built properly
 
I have heard of race trans shops building 904 with many 727 internals. Sure is easier than changing everything from kickdown linkage to drive shaft.
It's my experience that 904 just seems to transfer power to the road better than 727. Only once did I put a 727 in a A-body and took it back out 2 years later. Went back to the 904.
 
DON'T DO IT!... the 904 will be fine if built with quality parts and by someone thay actually knows what they are doing.. plus its smaller and lighter wich makes it easier to work with and a 904 will be faster.... that 727 over a 904 stuff is just an old school way of thinking.
 
I've been using the same Fireball 904 on my 340 with a B&M Holeshot converter for over 25 years. I change the oil every year or two, and use Ford fluid. My tranny builder says it is a little more abrasive and shifts quicker. As well I have a deeper pan and cooler installed.
 
Stick with the 904 properly built they can handle a LOT of power...
 
I also agree. Keep it a 904 unless your running a whole bunch of horsepower. Like 450 or above. If your just replacing the 904 cause it's bad it would be worth rebuilding it.
 
RedFish said:
I have heard of race trans shops building 904 with many 727 internals.
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Are you sure that isn't the other way around Redfish? Don't know how you could possibly fit 727 internals into a 904 cause the 904 case is approx. 2" smaller I.D.

I've seen 727's built with 904 internals though. The idea is use the lighter 904 parts that also have a lower 1st gear.
 
Hello, unless your making great power from the 360 I believe the 904 will do you fine... Kingfish
 
woow every other place i have asked (on-line) they said go with a 727. You guys rock and really know your stuff! :cheers::love7:

I have already had it rebuilt but since im going to pull my engine again i was thinking wither to stick with it or go to a 727. Any really good trans places around the Aptos CA area?

Im going to make about 325hp - 400hp what torque converter is right for me? I want acceleration more then top speed.
 
n00blike said:
woow every other place i have asked (on-line) they said go with a 727. You guys rock and really know your stuff! :cheers::love7:

I have already had it rebuilt but since im going to pull my engine again i was thinking wither to stick with it or go to a 727. Any really good trans places around the Aptos CA area?

Im going to make about 325hp - 400hp what torque converter is right for me? I want acceleration more then top speed.
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Yeah old school thinking was that a 727 is needed for any performance application but it's really not if your not running mega power.

Tell us more about your application as 325-400hp is a very broad spread. What cam, compression, intake, rear gears, tire size, car weight with driver or type of car if you don't know the weight. Need this info to make a judgement on the converter.
 
fishy68 said:
Yeah old school thinking was that a 727 is needed for any performance application but it's really not if your not running mega power.

Tell us more about your application as 325-400hp is a very broad spread. What cam, compression, intake, rear gears, tire size, car weight with driver or type of car if you don't know the weight. Need this info to make a judgement on the converter.
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In the latest Hot Rod issue there is a guy making a little over 600 horsepower in a 10 second Duster and he is running a rebuilt 904.
 
woow every other place i have asked (on-line) they said go with a 727.
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thats because too many people read that 25 years ago in a magazine and just can't accept the fact that over the years things actually change..

my 360 has had a 904 behind it for years now.. its gone a best of a 12.17 and has a tone of hard street miles.

mave a buddy with a 360 cuda going mid 11's with a 904. been in that car for over 1000 runs without a freshen up.

djvcuda has a 904 behind his 360 also.

have a buddy with a 10.80 340 demon that is running a 904.

they will hold a ton of power but have to be built properly.. and by properly i don't mean exotic parts... all you need is a guy that really knows what he is doing and quality parts.
 
My duster lays down 11.0's with the wheels up putting out 520 h.p.running a 904, trust me the 904 will serve you well,as for a converter give this guy a call www.ultimateconverter.com he's the best in the business..
 
abodyjoe said:
DON'T DO IT!... the 904 will be fine if built with quality parts and by someone thay actually knows what they are doing.. plus its smaller and lighter wich makes it easier to work with and a 904 will be faster.... that 727 over a 904 stuff is just an old school way of thinking.
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you could learn something from "old school thinking". 727 will last about 3 times longer on the street. I'd give up the tenth/ tenth and a half for lotsa durability. BB SS/AS and A/SA racers use 904 internals in a 727 case, but it would last a 1000 miles on the street. Once you get into the higher HP ranges (somethin' your not to familiar with) you'll realize the benifits of the "old School 727".
 
My Scamp (318, 904 combo) took ALOT of abuse. When I sold the car, the rear end was going out and the motor was blowing smoke out the exhaust. the only thing that was decent was the 904. I have a lot of respect for the 904. Especially when you put a 18-19 year old kid behind the wheel.
 
you could learn something from "old school thinking". 727 will last about 3 times longer on the street. I'd give up the tenth/ tenth and a half for lotsa durability.
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your right there are some thing you can learn from old school thinking. but is not this one... a 904 will last a long time behind a small block on the street.. like i said it needs quality parts in it and needs to be put together by someone that knows what they are doing but they will last a long time.

that old school thinking with the 904 and 727 arguement may have been true back in the day but now with all the clutches and band materials being so much better it doesn't hold water.. but hey everyone has their opinion.
 
abodyjoe said:
your right there are some thing you can learn from old school thinking. but is not this one... a 904 will last a long time behind a small block on the street.. like i said it needs quality parts in it and needs to be put together by someone that knows what they are doing but they will last a long time.

that old school thinking with the 904 and 727 arguement may have been true back in the day but now with all the clutches and band materials being so much better it doesn't hold water.. but hey everyone has their opinion.
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I agree, its like calling a 360 a dog next to a 340, its the old way of thinking, we now have parts to build the 360 just as good if not better than the 340, same goes for the 904 and 727
 
abodyjoe said:
your right there are some thing you can learn from old school thinking. but is not this one... a 904 will last a long time behind a small block on the street.. like i said it needs quality parts in it and needs to be put together by someone that knows what they are doing but they will last a long time.

that old school thinking with the 904 and 727 arguement may have been true back in the day but now with all the clutches and band materials being so much better it doesn't hold water.. but hey everyone has their opinion.
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yah ok, think about that the nexy time your 904 splits down the middle.
think that won't happen?
but i forgot there talkin' smallblocks...well until it gets to the 400+ cube territory. peeling out on the street is one thing, getting good hook at the track is another abuse wise. wonder why the factory never put 904's behind a bigblock? sure wasn't becouse of the HP #'s, so it musta been becouse of...........
 
my car launches ok with a wheel in the air. and i haven't hurt the 904 yet. hell i know quite a few people in this area that leave way harder then me and haven't had a problem with their 904, and they also do alot of street driving.. no problem.. quality parts by a guy that knows what he is doing.

no we aren't talking 1000 hp here. if we were maybe it would be different. but we arent.. you are comparing apples to oranges not apples to apples.

why didn't ma mopar put a 904 behind a big block? because 35 freaking years ago the materials wern't as good as they are now. times change and parts change.. is there anything wrong with going to a 727 besides having to get a new converter,yoke and driveshaft among other things? no. go for it if thats what you want.. will a 904 hold up just fine for what the original auther of this post wants it for? damn right it will...

like i said. everyone has their own opinion.. big and heavy is yours and light and efficient is mine.
 
abodyjoe said:
my car launches ok with a wheel in the air. and i haven't hurt the 904 yet. hell i know quite a few people in this area that leave way harder then me and haven't had a problem with their 904, and they also do alot of street driving.. no problem.. quality parts by a guy that knows what he is doing.

no we aren't talking 1000 hp here. if we were maybe it would be different. but we arent.. you are comparing apples to oranges not apples to apples.

why didn't ma mopar put a 904 behind a big block? because 35 freaking years ago the materials wern't as good as they are now. times change and parts change.. is there anything wrong with going to a 727 besides having to get a new converter,yoke and driveshaft among other things? no. go for it if thats what you want.. will a 904 hold up just fine for what the original auther of this post wants it for? damn right it will...

like i said. everyone has their own opinion.. big and heavy is yours and light and efficient is mine.
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the correct answer would be torque.
 
727's for fat overweight big block cars..904's for light "fast" small block cars..
 
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