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#2401646 - 11/10/17 08:19 PM Auto trans sbm choices ???
gogo318 Offline
member

Registered: 01/02/12
Posts: 100
Loc: waco tx
So we have a small block 450 horse n\a motor going in a lightened up 72 scamp 2dr every one has told me "727 and be done with it " but research tells me a built up 904 is quicker and lighter and just as tough and i have a good core for one aswell but i recently fell into a short tail 727 out of a 73 4x4 and im hearing from a few folks they have a " violent " first gear when used for racing .....whats that mean ? Is it worth building or am i better off continuing my 904 idea?
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67 charger fastback 318 stock 67 belvedere II 4dr soft top built 318 68 newport 2dr hard top 318 84 b150 440/727 84 d150 short wheel step side 4x4 lifted 87 omnitruck (you just have to see it ) new addition 63 dart wagon !!!

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#2401659 - 11/10/17 08:40 PM Re: Auto trans sbm choices ??? [Re: gogo318]
larrymopar360 Offline
super stock

Registered: 01/07/11
Posts: 970
Loc: Melbourne, Florida
I would guess they mean a hard 1st to 2nd shift?

I have a 470hp/525ft.lb. torque stroked small block with a TCI 727 with over 40,000 miles and no complaints. I think they reportedly had some quality control issues, but this is my second with no issues. Previous one had 60,000 miles. It's the 727 "Streetfighter" auto valve body. Little chirp in second at WOT. I prefer the 727 for it's beefier size despite it's increased weight, although I've heard the smaller t-flites can be built to handle high HP.
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1979 Power Wagon Adventurer short bed factory 360-4
1989 Diplomat ex-police 410 c.i.d. small block
2014 Charger Pursuit 5.7

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#2401670 - 11/10/17 08:55 PM Re: Auto trans sbm choices ??? [Re: gogo318]
topside Online   content
I Live Here

Registered: 01/19/03
Posts: 11509
Loc: So Near, Yet So Far
With 450HP - how much torque? - in a sub-3000-lb car, the 904 will work with good clutches & bands. I'll assume no transbrake. The 727 is stronger, takes a little more HP to drive, which may amount to .1-ish ET. That said, if you get greedy and plan on 600HP or a transbrake, the 904 will need a little more aftermarket help than an equivalent 727. My basically stock 904 held up well until I put more than 600HP to it in a low-10s 3000-lb SB Duster; after that a mid-range CRT 904 was necessary. (6000 stall, footbrake car.)
Call John @ CRT - he's a member here - and tell him your combo & goals; he'll treat you right.

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#2401690 - 11/10/17 09:34 PM Re: Auto trans sbm choices ??? [Re: gogo318]
340Cuda Offline
top fuel

Registered: 04/04/03
Posts: 1609
Loc: Tulsa, Oklahoma
The 904 will normally be at at least a tenth faster. However like has been said, it takes money to keep them strong enough as the power goes up, that includes the torque converter that will need a premium snout early on.

The recommendation to call John is a good one.

Bill

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#2401691 - 11/10/17 09:34 PM Re: Auto trans sbm choices ??? [Re: gogo318]
340Cuda Offline
top fuel

Registered: 04/04/03
Posts: 1609
Loc: Tulsa, Oklahoma
The 904 will normally be at at least a tenth faster. However like has been said, it takes money to keep them strong enough as the power goes up, that includes the torque converter that will need a premium snout early on.

The recommendation to call John is a good one.

Bill

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#2401725 - 11/10/17 10:48 PM Re: Auto trans sbm choices ??? [Re: gogo318]
humpty Offline
enthusiast

Registered: 10/17/07
Posts: 283
Loc: Minnesota, USA
I swapped a 727 out for a low gear 904 with a trans brake a couple years ago and wouldn't hesitate to do it again. I had it apart this year after 200+ passes and everything looks fresh. Call John at CRT and he'll take good care of you. They are easy to build yourself if you have the patience and do some research.
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72 Duster - 408ci W2 iron headed SB, 1.41 60', 6.43@105, 10.18@131.

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#2401729 - 11/10/17 10:59 PM Re: Auto trans sbm choices ??? [Re: gogo318]
gogo318 Offline
member

Registered: 01/02/12
Posts: 100
Loc: waco tx
Noted on calling john i will and the 904 was my first choice for all the right reasons i was just curious aboit this short tail shaft trans and if it was better for launching no trans brake
_________________________
67 charger fastback 318 stock 67 belvedere II 4dr soft top built 318 68 newport 2dr hard top 318 84 b150 440/727 84 d150 short wheel step side 4x4 lifted 87 omnitruck (you just have to see it ) new addition 63 dart wagon !!!

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#2401732 - 11/10/17 11:04 PM Re: Auto trans sbm choices ??? [Re: gogo318]
DaveRS23 Offline
master

Registered: 01/20/03
Posts: 4413
Loc: Benton, IL.
With the same attention to details when building each tranny, a 727 won't be any more "violent" than a 904.

I guess there could be some unique situations that could favor the 727 in your application. But with the information at hand, I would go with the 904 for the reasons already noted. I have ran them in heavier cars than yours with warmed up 360s and they have always worked and held up very well.
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KOS

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#2401733 - 11/10/17 11:05 PM Re: Auto trans sbm choices ??? [Re: gogo318]
J_BODY Offline
I Live Here

Registered: 04/30/03
Posts: 11128
Loc: aZLiViN
I've fought some interesting breakage with my 727, but it's lived 30 passes so I might have it behind me. Of course, once it proves itself I'm pulling it out and putting my mild 904 in. 2970lb car off the trans brake running mid 9's.... what could happen! smile

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#2401751 - 11/11/17 12:15 AM Re: Auto trans sbm choices ??? [Re: gogo318]
Michael Ecks Online   content
super stock

Registered: 01/20/03
Posts: 1023
Loc: Columbus, GA
Is this for street or strip?

For street use I'm in the 727 and be done with it camp. Went through a few 904s including one where the converter snout broke off and ruined the rest of the trans.

I have a TCI streetfighter 727 in the car with a PTC converter and feel way more confident in its durability. For a strip car where worst case scenario is having to push it to the pits and load it onto a trailer, build all the 904's you want. They are definitly lighter, but don't kid youself that they are as tough as a 727 with equal quality/type of parts in each. There's a reason engineers didn't put 904's behind big blocks.

As to the violent first gear thing, so far as I know all 727s have the same gearing. The people telling you that may be confusing them with later model 904s (999?) that had a lower first gear. Behind a stout motor with low rear end gears it would make for a pretty violent launch followed by a pretty boggy 1-2 shift because of the wider ratio split between the two.
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"The happiness of your life depends upon the quality of
your thoughts" ~ Roman Emperor Marcus Aurelius

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#2401786 - 11/11/17 07:40 AM Re: Auto trans sbm choices ??? [Re: gogo318]
Bad340fish Offline
master

Registered: 01/20/03
Posts: 5336
Loc: Tulsa OK
If you want to set it and forget it go 727. Mine is 16 years old and has tons of miles and passes on it and it still shifts amazing. That being said my car is over weight and I will be swapping to a 904 or low gear 904 over the winter.
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68 Barracuda Formula S 340

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#2402082 - 11/11/17 04:48 PM Re: Auto trans sbm choices ??? [Re: 340Cuda]
John_Kunkel Offline
I Live Here

Registered: 01/20/03
Posts: 18838
Loc: Rio Linda, CA
Originally Posted By 340Cuda
The 904 will normally be at at least a tenth faster.


And what does that tenth get you in a bracket car? Bragging rights is all.
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I'm supposed to respect my elders, but its getting harder and harder for me to find one now.

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#2402882 - 11/12/17 11:26 PM Re: Auto trans sbm choices ??? [Re: J_BODY]
Just-a-dart Offline
super stock

Registered: 02/20/11
Posts: 1091
Loc: Glendora Ca.
Originally Posted By J_BODY
I've fought some interesting breakage with my 727, but it's lived 30 passes so I might have it behind me. Of course, once it proves itself I'm pulling it out and putting my mild 904 in. 2970lb car off the trans brake running mid 9's.... what could happen! smile


Jay sometimes I think you just try to be a bad example. ha ha

904 for me, faster fits better. They all need good parts
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"Just a Bracket car dressed up like a streetcar"

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