A904 Lock up performance build

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Archeryguy02

Archeryguy02

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I pulled this transmission out of a 5.2 magnum swapped 68 valiant I bought a few years ago. From what I can tell decoding the numbers it came out of a 82 Cordoba(I was told it came from a Cordoba) and the shaft is a lock up type from what I have read.

It works just fine but I am upgrading the car for more strip time than street time and am wanting to know how good of a base for a bracket 904 this transmission is. I want something that will live for multiple years behind a 400-500hp small block. Is this a good starting point or should I get a non lock up 904 and save this for a cruiser?

Please don't mention a 727 I am only interested in a 904 for this car.

Thank you in advance.

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CudaFactHackJob said:
Is this going to be a diy build thread?
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I am not sure if I want to try and do the work myself or not. It could be but I am more interested in knowing what parts are available and what kind of starting point this is before I get to that point. To this point most performance parts tend to end around 77 or 80 for 904's from what I have seen.
 
I run one out of an 84 diplomat. All OEM with TF2 shift kit, Lockout circuit plugged, TA 10" 3400 converter. 340, high 11s 12.0 car. Street driven and 1k passes.
 
Call John Cope he can help you with the parts, valve body, low gear sets etc. he is all mopar all the time...
 
I'd like to see a thread on building a 904 with 999 guts that utilizes a non lockup converter, but retains the five plate direct clutch and wide front band.
 
mderoy340 said:
I run one out of an 84 diplomat. All OEM with TF2 shift kit, Lockout circuit plugged, TA 10" 3400 converter. 340, high 11s 12.0 car. Street driven and 1k passes.
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This is great info and about where I want this car to run to stay in the sportsmen class. Did you just buy a regular 904 stall converter or something special for the lockout tranny?
 
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Archeryguy02 said:
This is great info and about where I want this car to run to stay in the sportsmen class. Did you just buy a regular 904 stall converter or something special for the lockout tranny?
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Turbo Action sells converters with no converter clutch but with the lockup spline count. Call them and talk to Paul Forte. I paid approx 600 for mine S800 tight 3400 flash.
 
mderoy340 said:
Turbo Action sells converters with no converter clutch but with the lockup spline count. Call them and talk to Paul Forte. I paid approx 600 for mine S800 tight 3400 flash.
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When you installed the TF2 did you drill the 2 holes specified for the lock up models?
 
Sorry to intrude, but what's wrong with a lockup trans/converter for performance? I really don't know much about transmissions so this is a real question.
 
Cuda416 said:
Sorry to intrude, but what's wrong with a lockup trans/converter for performance? I really don't know much about transmissions so this is a real question.
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I need a stall to help launch the car and this one locks up pretty tight at about 1100 rpm so the car is a bit sluggish out of the hole. It would be fine for mild street driving and cruising. I am not finding anything about a stall converter that actually locks up, but I am learning as I go with this project. I have the tranny apart and the shift kit nearly completely installed but need to determine a few more mods that revolve around the lock up aspect as per my questions asked above.
 
If it spends time at the track with 500 horse under the hood why not have a purposely built 904 built and sell your lock up. Street guys like those.
 
Archeryguy02 said:
I need a stall to help launch the car and this one locks up pretty tight at about 1100 rpm so the car is a bit sluggish out of the hole. It would be fine for mild street driving and cruising. I am not finding anything about a stall converter that actually locks up, but I am learning as I go with this project. I have the tranny apart and the shift kit nearly completely installed but need to determine a few more mods that revolve around the lock up aspect as per my questions asked above.
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Ahh, didn't know that. Seems I have some research to do. For some reason I had it in my head lockups were a good thing. Thanks
 
Archeryguy02 said:
I need a stall to help launch the car and this one locks up pretty tight at about 1100 rpm so the car is a bit sluggish out of the hole. It would be fine for mild street driving and cruising. I am not finding anything about a stall converter that actually locks up, but I am learning as I go with this project. I have the tranny apart and the shift kit nearly completely installed but need to determine a few more mods that revolve around the lock up aspect as per my questions asked above.
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Lock up converters shouldn't lock up until you are in 3rd gear. Sluggish out of the hole could be a half dozen different things not related to your transmission.
 
toolmanmike said:
Lock up converters shouldn't lock up until you are in 3rd gear. Sluggish out of the hole could be a half dozen different things not related to your transmission.
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I appreciate your help but you may be misunderstanding what I said. I am aware of when lock ups are supposed to lock up. My first words were I need a stall converter, do you have a link for high stall converters available that are lock up? The car will typically light up both tires from an idle on the street, but the motor gets really happy around 3000rpm so I would like to take advantage of that on the track. Maybe I should have made the title of the thread more specific. Although I started it to learn about these transmission and my options before I spent any money on this tranny. I have learned enough to get me to where I feel comfortable moving forward thanks to individuals here that have pointed me in the right direction as well as research based on that direction.

toolmanmike said:
If it spends time at the track with 500 horse under the hood why not have a purposely built 904 built and sell your lock up. Street guys like those.
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A few reasons for my wanting to keep this one.

1. I have it already.
2. I know it works well at this point aside from needing a higher stall for my needs.
3. I doubt I could sell it and buy a replacement that is guaranteed good without a substantial financial expenditure.

If I was doing a total rebuild or starting from scratch I would totally agree with you.
 
Archeryguy02 said:
I appreciate your help but you may be misunderstanding what I said. I am aware of when lock ups are supposed to lock up. My first words were I need a stall converter, do you have a link for high stall converters available that are lock up? The car will typically light up both tires from an idle on the street, but the motor gets really happy around 3000rpm so I would like to take advantage of that on the track. Maybe I should have made the title of the thread more specific. Although I started it to learn about these transmission and my options before I spent any money on this tranny. I have learned enough to get me to where I feel comfortable moving forward thanks to individuals here that have pointed me in the right direction as well as research based on that direction.



A few reasons for my wanting to keep this one.

1. I have it already.
2. I know it works well at this point aside from needing a higher stall for my needs.
3. I doubt I could sell it and buy a replacement that is guaranteed good without a substantial financial expenditure.

If I was doing a total rebuild or starting from scratch I would totally agree with you.
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Precision of New Hampton | Torque Converters, Transmission Contact them and tell them what you have. They can build you one.
 
Cuda416 said:
Ahh, didn't know that. Seems I have some research to do. For some reason I had it in my head lockups were a good thing. Thanks
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Based on what I have learned to this point lock ups are fine for street driving and gas mileage, although some of the early ones caused some bogging and chugging issues from what I have read. I believe the issues mentioned can be cured by stiffer springs.
 
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The biggest drawback to the lockup transmissions is the lack of off-the-shelf performance converters.
 
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