727 or 904 which way to go

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dodgeboy

dodgeboy

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i have a 727 that has been sitting for several yrs obviousily is goin to need rebuilt that a guy wants he is wanting to swap a rebuilt 904 he wants the 727 to put in his derby car which way should i go keep the 727 and rebuild it myself or swap and take the 904 my dart will see mostly street use with the occasional trip down the 1/4 mile.not building a super aggresive motor.
 
If the 904 isn't beefed up to handle a V-8 keep the 727 and build that.
 
904 - They came in V8s, 273s 318s and some 360s. Good strong tranny that can handle a mild build. Also lighter than a 727 and takes less power than a 727.
 
Demon416 said:
If the 904 isn't beefed up to handle a V-8 keep the 727 and build that.
Click to expand...

Yes..the 904 is beefed up to handle a V-8...put a good set of clutches/disc...and good set of bands...and you are BEEFED....
 
I'd run a 904 if it was me. A correctly rebuilt stock 904 will handle 325-350 hp and if you add a good shift improver kit such as a Trans-Go it's capacity jumps up to 375-400 hp. Put in a good set of red clutches and bands and your at 450 hp capacity. The only concern I'd have would be was the 904 really rebuilt? And if so was it done right? So many guys will flat out lie about stuff saying it's rebuilt when it hasn't even been touched and others don't know enough of what their talking about and will call something rebuilt when all it's had was a filter change that I don't trust anyone unless I know them really really well.

Hey I've been through Greenup before. Spent a lot of time working in the Effingham area as a Hyster forklift mechanic.
 
Fishy68,.. a question please???

Do you have to build up a 904, ie.-- bands, clutches, and my personal question, do you need after-market planetaries,, to be as strong as a stock 727, diss-regarding h/p loss..

just really interested/respect your opinion.. thnx grant..

Tracy,.. I 've been here a coupla years, and am learning that--if you want to spend bucks, modify a 904,, or on a budget, run a stock 727 with a kit..

would that be fair,,.. for a budget build,.. thnx
 
Grant you'd have to do quite a bit to make it as strong as a 727 cause the 727 parts are so much larger. One big drawback is the smaller diameter of the input shaft and converter hub. Then there are the planetaries. You'd need aftermarket ones to make it as strong as a 727. Nevertheless, you can build a 904 to stand up to 500 hp fairly easy. But the same build on a 727 will take 600 hp. One drawback to consider on a 727 is the larger spinning mass not only eats hp but is more prone to exploding so when you get serious with them you should replace the front clutch drum and add a good bolt in sprague for safety
 
Thnx Tracy,,

I guess thru all the posts, I kept seeing folks saying use a 904,, leaving out the part, it needs to be a "built" 904.. in place of a stockish 727, (with a kit)

I replaced a lotta blown up 904 planetaries ,and have a hard time believing stock 904 planetaries endure, , we most often replaced the trans with a whole 727 trans...
some Taxi fleets... the owners didn't buy the H/D taxi/police pkg...


May I ask what an aftermarket planetary is worth,.. tia


thnx for the clarification.. grant
 
Go 904.I have a bulletproof 727 that came with my car.You are looking at .15 to .2 tenths,ET wise.Go for it.
 
great thread, i'm asking myself the same question....leaning towards 727 for piece of mind without breaking the bank:)
 
That exactly what it rools to.Myself,I prefer durability(and stock).You can always make horsepower.The tranny build on my 727, hammers when I ask it to.I know it won't fail,by virtue of it's design.
 
I say keep your 727 cause its gonna get trashed in the derby, buy a 904 at swap meet and build it yourself beef it up the way you want to.
 
I went back and forth on this. I have both a 904 and a 727 in similar condition. I'm going to rebuild the 727. Just ordered the kit from Cope. The 904 would have cost quite a bit more to upgrade, the 727 is just getting upgraded bands and steels. I also am putting it behind a 360 so the 904 would have needed work with the external balance but that is pretty much offset by the 727 needing a shortened driveshaft.
 
904's don't grenade like 727's can.

I'll take a 904, especially behind a SB.
 
Lots of small block drag cars run 904's
 
Hersbird said:
I went back and forth on this. I have both a 904 and a 727 in similar condition. I'm going to rebuild the 727. Just ordered the kit from Cope. The 904 would have cost quite a bit more to upgrade, the 727 is just getting upgraded bands and steels. I also am putting it behind a 360 so the 904 would have needed work with the external balance but that is pretty much offset by the 727 needing a shortened driveshaft.
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the 904 would have only needed upgraded band and steel/disc. ...the transmission does not need anything for an external balance...the flexplate or converter needs weights for the external balance not the trans.

i hope CRT sends you a jar of assembly lube also...

I am currently using 904 in my 3 race cars...one trans has been in use since 1993 with only one rebuild....and they have nothing but alto clutches and kolene steels along with a kevar band...and the front drum spring kit...that is it...
 
Well the converter and flexplate is part of the transmission if you ask me. No matter how you slice it the 904 costs more to build and what do you get? A fraction in the 1/4 mile? we don't even have a track. Even the basic kit is more because my 904 is a 68 and the 727 is a 72. My driveshaft has to be shortened to get rid of the 7 1/4 anyway. Probably why I have $100 jegs headers not $600 TTIs. All of these $100 bills add up, it's all about bang for the buck for this single income blue collar family. Maybe it would be fun to piss money on multiple toy race cars, but for now I'll just have fun in the corner with my assembly lube!
 
I think what tony is saying is you could have saved money buying the same parts from other suppliers. All most of the shops do is rebox the items in a transtar kit. It doesn't cost any more money for a 904 rebuild kit ~125, than a 727, .

Converters cost the same across the board. You need a good flexplate anyways, so that's a wash.

Don't lose a driveshaft, rear gear in 1st gear with a 727. They can get ugly!

Pick your parts, pay your money
 
In my experience 904s can be cheaper. Most people give them away and I too have had a 904 in my street/race car and it has NEVER broken. IMHO the 904 will make a difference between, "yeah it runs okay" and "holy sh&t that thing runs!"
 
In my case I was going from a 68 318 904 to a 72 360 727. By keeping the 727 with the 360 I an reusing the factory 360 torque converter. Had I put the 904 behind the 360 I would have had to spend more to make it work. Also the 72 parts are less then the 68 parts. All in all it's a good $200 less. Like I said I went back and forth and it came down to money, the 727 is just less expensive, it came with the 360 I bought, I think I paid maybe $100 for the motor and tranny, but it might have been included with the $300 Duster I bought for the K frame-brakes setup. It's been like 6 years and I forget.
70aarcuda I wasn't trying to be an ***, I appreciate your opnion, I was just trying to be funny with the lube crack.

PS, maybe if transtar put up a regular webpage to order from or had a location within 3 hours of me, who knows. As it stands $155 shipped for a soft kit with red eagle and kolene steels seemed pretty low. Simple ordering, good price, I have NO problem with Cope.
 
Hersbird said:
"but for now I'll just have fun in the corner with my assembly lube!"
Click to expand...

I'm sorry, but that is pretty dang funny, chuckled a bit on that one.

Back on subject; I have a similar thread but chose the 904 to keep the push button shifter & a 727 would be chore to wedge into this little '63 Valiant. So I chose it out of convenience. What did your car originally have in it? Just out of curiosity. If you already mentioned it, please forgive me, I believe I am sleep typing considering the time of nite.
 
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