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Thinking of going TH400

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Old May 3, 2009 | 08:46 PM
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Default Thinking of going TH400

OK guys. Ive currently got a T56 in my car and am thinking of swapping to a TH400. My question is, who here is running them, with what stall and what rear gear, tire size, and what is your RPM at lets say 75 mph? I know they dont have any lockup, and that is my only worry. Ive currently got a heads/cam car (specs in sig) with a 4.10 gear, and plan to keep with this gear, and go to a 28 tall tire. Please, any info or recommendations are appreciated!!
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Old May 3, 2009 | 09:16 PM
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At 75 MPH you'll be at 3899 RPM with 4.10's, 28" tires.

Rear gear x 355 x MPH / tire diameter = RPM

(FYI- 355 is for a high stall converter and unlocked, a lot of calculations use 336 but thats more for manual transmissions, locked up converters or stock low stall.) And for overdrives it's rear gear x OD ratio x 355 x mph / tire = rpm.
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Old May 3, 2009 | 09:18 PM
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holy bajesus!!! No way in hell that right there would work.... Im thinking of going like a 3800 stall.
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Old May 3, 2009 | 09:39 PM
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Yes I think I spoke with you. If this car does anything other than race I would really consider either a 4L60E if under 600-700 hp if over and since your swapping anyway a 4l80e might also be a consideration.
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Old May 4, 2009 | 02:00 AM
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I'm running a TH350 with 4.11s and a 27" tire. I'm at 3300 RPM at 65 mph
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Old Jun 6, 2009 | 12:19 AM
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Originally Posted by Z28/2002
I'm running a TH350 with 4.11s and a 27" tire. I'm at 3300 RPM at 65 mph
same here with my th400. but on 28" tire.... i think at 70 MPH im at 3500
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Old Jun 7, 2009 | 08:09 AM
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Originally Posted by Raven02TA
same here with my th400. but on 28" tire.... i think at 70 MPH im at 3500
That's not too shabby
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Old Jun 7, 2009 | 08:55 AM
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400th great for drag car but if drive on street you should look into 4l80/4l85e swap.the swap is easy a is money well spent .they are also just as strong as th400 but way better on street.
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Old Jun 7, 2009 | 09:58 AM
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i have a TH400, 325 radial (28") and 373 gear. i am at 3500 rpms at 70 mph and its pretty comfortable with a quiet exhaust. i never do more than 70 mph other than at the track or i get a hair up my *** and feel like hammering it.
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Old Jun 7, 2009 | 11:32 AM
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I agree with the above, If you're going to drive it everyday, the 4L80 would be the way to go.

I'm moving from a T56 to a th400, but my car will not be daily driven. I already have the th400, it has a 3200 precision stall in it. The car will be on a 28'' tire with 2.75's in the back. I'm going with a low gear because I will be running against bikes and what not on the highway.
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Old Jun 23, 2009 | 11:07 PM
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Originally Posted by 99Z28LS1
I agree with the above, If you're going to drive it everyday, the 4L80 would be the way to go.

I'm moving from a T56 to a th400, but my car will not be daily driven. I already have the th400, it has a 3200 precision stall in it. The car will be on a 28'' tire with 2.75's in the back. I'm going with a low gear because I will be running against bikes and what not on the highway.
Nice building a bike killer! pm me when you wanna test it out
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Old Jun 24, 2009 | 02:37 AM
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do keep in mind also that th400's are known for useing a lot power to turn themselves, on average 150 to 200 horspower.

an aquaintance had a 400 with a 3200 stall in an 04 gto with a 408, he drove it daily for a while, loud exhaust and all. after not long he hated it and just recently switched back to a t56. he was at roughtly 3000rpms at 65mph
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Old Jun 24, 2009 | 08:56 AM
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Originally Posted by CarsandWomen
do keep in mind also that th400's are known for useing a lot power to turn themselves, on average 150 to 200 horspower.

an aquaintance had a 400 with a 3200 stall in an 04 gto with a 408, he drove it daily for a while, loud exhaust and all. after not long he hated it and just recently switched back to a t56. he was at roughtly 3000rpms at 65mph
I don't think a 400 eates 150-200 hp.
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Old Jun 24, 2009 | 12:11 PM
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I don't think a th400 would be all that bad, just don't put gears like 4.10s in your rear and you should be ok.
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Old Jun 24, 2009 | 12:45 PM
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TH400 for racing. No other reason to do it, unless you just want to save a bunch of money by not going 4l80e.

Plenty of TH400's in the junkyard.
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Old Jun 25, 2009 | 12:14 AM
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Originally Posted by built408
I don't think a 400 eates 150-200 hp.
every one ive ever seen engine dyno and chassis dyno numbers for did. Thats allowing for rear end accesories. Its that high IMO. Its been my experiance they eat more power the more built up they become.

everything ive heard is they suck more power than most. really the only way to find out would be an engine dyno with a couple different trans behind it. my .2.

Built408, whats your estimate for their power consumption? Are you aware of their reputation for it? Not trying to be a dick, im looking for your honest opinion.
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Old Jun 25, 2009 | 08:58 AM
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Who cares, the gearing is better than the 4L60E anyways. You might not put out more hp, but if track times are what matters, then the TH400 is the way to go.
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