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What stall speed for fox body with AOD trans?

2330 Views 5 Replies 5 Participants Last post by  Cobrajet67
I am sure this has been batted around before but automatic transmissions are something I have always avoided. :sleep:

Now I have a 1989 fox body with 5.0 and AOD trans. I am looking at doing some work on the car this winter and will be replacing the stock heads with the better flowing GT40P heads from a Ford Explorer as well as the better flowing intake manifold. Next a slightly larger throttle body, a better flowing fuel pump and regulator, larger injectors, and cold air. And shorty headers with new exhaust. And a new cam. And that is everything (ha!).

I will be rebuilding the AOD so while I am at it I am wondering, what stall speed should I anticipate needing for the torque converter? The cam will likely be an E303 or similar. I am hoping that some of you folks have gone down this road before and will offer advice based on my intended mods. Thanks for the help.

Randy in Everett, WA
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If it's a car that's driven on the street(presumably) then a torque converter that isn't a really high RPM stall speed would be best. I think a stock AOD converter in a GT already has an almost 1400rpm stall(1300 something from what I remember). So probably about a 500rpm or so over stock which would be like an 1800-2000rpm converter would be good choice imo. You would benefit with even a mild converter for the street.
The mods you describe aren't going to have you need a really high stall converter. You're essentially planning on making a slightly hotter late model 5.0 Explorer engine since a late 1990s Explorer would have had many of the parts that you're describing already sans the cam of course. The E303 isn't a high RPM screamer cam where a higher stall converter might be beneficial for the track. It's a good low-mid RPM street cam that will give you good street manners, retain decent vacuum, and a reasonable idle.
For an AOD trans TCI makes the Saturday Night Special which is about 500rpm over stock and good for mild builds. It retains the lock up and this is what I had bought for my 1991 GT. Then they jump to the Streetfighter which is about 1500rpm over stock which is quite a bit for a street car imo. You have a lock up or non-lock up version with that choice.
There's plenty of other brands out there too that may give you an option in the middle closer to 2200rpm.
Take note that the higher the stall RPM the hotter the trans will run especially at lower speeds as you'll also have more slipping. A non-lock up converter will also generate more heat at higher speeds so I recommend a lock up.
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Usually the cam manufacturer will suggest a converter stall speed Trick Flow recommended a 2500-3000 rpm stall speed for my TFS Track Heat Stage 2 Roller Cam. I actually went with a Monster 2800-3200 rpm stall.
It'll really depend on the cam profile. If it's a higher RPM cam then a higher RPM stall converter would be helpful but only so much for street use. The OP's planned cam is a low to mid RPM cam which will be best for the street therefore a high stall converter will not be helpful to him.
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