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Re: What makes a TH400 stronger than a 727?
[Re: JohnRR]
#3227940
04/18/24 05:20 PM
04/18/24 05:20 PM
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Joined: Mar 2011
Posts: 3,075
Michigan
A727Tflite
master
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master
Joined: Mar 2011
Posts: 3,075
Michigan
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AS said its more the availability of aftermarket parts. There are many parts out there to make a 727 live at that power level. With a TH400 there are just more options, kinda like a BBC vs a BBM. Both capable of making power one just has many more options. The one thing you cannot get for a 727 is an SFI case, to me that s a big deal. FWIW my 64 Savoy has a 727 built by Joels on Joy, it makes north of 1000hp. From what I've been told torque is the larger issue with a TF than raw HP. The Vette has an A1 built 727 and it makes a tick over 1100hp. They are both very nice pieces but are not a budget friendly one. You are correct it's the torque that is the issue vs. the HP level. That said the diesel market is building 47/48RE's that handle over 2000 lb/ft of torque so it's doable , an SFI case would be nice though. Thank you, someone finally gets it.
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Re: What makes a TH400 stronger than a 727?
[Re: A727Tflite]
#3228042
04/19/24 11:09 AM
04/19/24 11:09 AM
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Joined: Jan 2003
Posts: 75,004
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,004
U.S.S.A.
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AS said its more the availability of aftermarket parts. There are many parts out there to make a 727 live at that power level. With a TH400 there are just more options, kinda like a BBC vs a BBM. Both capable of making power one just has many more options. The one thing you cannot get for a 727 is an SFI case, to me that s a big deal. FWIW my 64 Savoy has a 727 built by Joels on Joy, it makes north of 1000hp. From what I've been told torque is the larger issue with a TF than raw HP. The Vette has an A1 built 727 and it makes a tick over 1100hp. They are both very nice pieces but are not a budget friendly one. You are correct it's the torque that is the issue vs. the HP level. That said the diesel market is building 47/48RE's that handle over 2000 lb/ft of torque so it's doable , an SFI case would be nice though. Thank you, someone finally gets it. I built a number of them 20 some years ago for 500 - 650 HP trucks , that's over 1000 lb/ft , this was before they had hardened output shafts for the OD units which I twisted off doing a brake stand once in my own truck 
running up my post count some more .
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Re: What makes a TH400 stronger than a 727?
[Re: an8sec70cuda]
#3228234
04/20/24 10:12 AM
04/20/24 10:12 AM
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Joined: Jan 2003
Posts: 8,164
Plymouth, MI
Blusmbl
master
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master
Joined: Jan 2003
Posts: 8,164
Plymouth, MI
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[quote=Blusmbl]Nick...my 727 is still living, but I don't race my car very often. I killed a sprag a few years ago that took out the case. It let go mid wheelie in 1st gear, crunched the oil pan, but drove back in the trailer.
It still has stock shafts in it, but it wouldn't surprise me if it broke one on its next pass.
I have a 5 pinion steel planet, billet steel drum, non LBA Turbo Action transbrake, deep cast aluminum pan, etc. Nothing real fancy.
My car will go 8.60s, but my best 60' is a 1.30 (may not have tripped the beam w/ the front tire?).There's a fine line b/t wheel spin and wheel stand w/ my combo.
That's helpful too, thanks Chip! I'm heavier but am definitely going to be making less power and torque than you. Do you normally run your car at the track on slicks or the radials? And one other question, is the LBA stronger for situations like those, or would the sprag have failed anyway even with a LBA valve body?
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Re: What makes a TH400 stronger than a 727?
[Re: Blusmbl]
#3228272
04/20/24 01:23 PM
04/20/24 01:23 PM
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Joined: Jan 2022
Posts: 138
Connellsville
71Demon528
member
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member
Joined: Jan 2022
Posts: 138
Connellsville
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[quote=Blusmbl]Nick...my 727 is still living, but I don't race my car very often. I killed a sprag a few years ago that took out the case. It let go mid wheelie in 1st gear, crunched the oil pan, but drove back in the trailer.
It still has stock shafts in it, but it wouldn't surprise me if it broke one on its next pass.
I have a 5 pinion steel planet, billet steel drum, non LBA Turbo Action transbrake, deep cast aluminum pan, etc. Nothing real fancy.
My car will go 8.60s, but my best 60' is a 1.30 (may not have tripped the beam w/ the front tire?).There's a fine line b/t wheel spin and wheel stand w/ my combo.
That's helpful too, thanks Chip! I'm heavier but am definitely going to be making less power and torque than you. Do you normally run your car at the track on slicks or the radials? And one other question, is the LBA stronger for situations like those, or would the sprag have failed anyway even with a LBA valve body? Yes LBA is the safest way to go to protect the sprag. Period. All the load is on that sprag in first gear. No matter if you have a bolt in 16 element or not, it can still fail. So if it fails, it’s only in first gear because the sprag is holding the low reverse drum from spinning counter clockwise then once you shift into second gear the sprag begins to overrun, hence the term overrunning clutch. So the L/R drum begins to spin clockwise freely in 2nd and 3rd gear with no load on the sprag. The low band apply protects the sprag so now the L/R band is helping dampen the load the sprag sees in 1st gear.
Last edited by 71Demon528; 04/20/24 01:29 PM.
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Re: What makes a TH400 stronger than a 727?
[Re: JohnRR]
#3228496
04/21/24 09:53 PM
04/21/24 09:53 PM
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Joined: Dec 2003
Posts: 581
Boise Idaho
65coronet500
mopar
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mopar
Joined: Dec 2003
Posts: 581
Boise Idaho
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I’ve built 47/48 re’s for guys right at the 2000 horse level and pushing 3000 lb ft of torque !
Do they live long? Depends on the weight of the truck and gear ratio and of course your right foot!
The technology is definitely there for the flite to live and be reliable at most gasoline power levels we just need the Sfi case to make it all work out best
I’m surprised A&A or Cope hasn’t built a case ?
All steel 3800 lbs with me in it 65 Coronet 451 CID Indy 440-1 heads by Dwayne Porter racing heads .
..... 10.31 @ 129.4 mph 1.40 60 ft ALL MOTOR!!!!
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Re: What makes a TH400 stronger than a 727?
[Re: Blusmbl]
#3228558
04/22/24 09:23 AM
04/22/24 09:23 AM
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Joined: Jan 2003
Posts: 13,360
Marion, South Carolina [><]
an8sec70cuda
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 13,360
Marion, South Carolina [><]
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[quote=Blusmbl]Nick...my 727 is still living, but I don't race my car very often. I killed a sprag a few years ago that took out the case. It let go mid wheelie in 1st gear, crunched the oil pan, but drove back in the trailer.
It still has stock shafts in it, but it wouldn't surprise me if it broke one on its next pass.
I have a 5 pinion steel planet, billet steel drum, non LBA Turbo Action transbrake, deep cast aluminum pan, etc. Nothing real fancy.
My car will go 8.60s, but my best 60' is a 1.30 (may not have tripped the beam w/ the front tire?).There's a fine line b/t wheel spin and wheel stand w/ my combo.
That's helpful too, thanks Chip! I'm heavier but am definitely going to be making less power and torque than you. Do you normally run your car at the track on slicks or the radials? And one other question, is the LBA stronger for situations like those, or would the sprag have failed anyway even with a LBA valve body? Nick...the sprag was probably damaged on one of the many passes when I was sorting out the suspension. I would rather have a LBA valve body in it honestly, but I'm using what I have. I always run radials. I tried slicks several years ago and it didn't work well at all. Nothing works if you have too much SLR.
CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
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Re: What makes a TH400 stronger than a 727?
[Re: dvw]
#3228650
04/22/24 08:55 PM
04/22/24 08:55 PM
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Joined: Jan 2022
Posts: 138
Connellsville
71Demon528
member
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member
Joined: Jan 2022
Posts: 138
Connellsville
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We failed the sprag on Dizusters car with LBA. But for sure it helps. I dont run LBA because the 1/2 shift isn't quite as quick. And not using a trans brake it lives pretty well. If I remeber correctly some trans brake valve bodies have a timed release of the low band. best of both worlds.
Doug I’ve never noticed any difference in the 1-2 shift between A&A nonLBA and the A&A LBA. I only ever noticed a difference with quickness of the 1-2 shift when going from the turbo action valve body to theA&A both non LBA and LBA. How did you manage to kill a sprag with a LBA? That’s impressive lol.
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Re: What makes a TH400 stronger than a 727?
[Re: 71Demon528]
#3228752
04/23/24 12:13 PM
04/23/24 12:13 PM
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Joined: Jan 2003
Posts: 25,783
Rio Linda, CA
John_Kunkel
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 25,783
Rio Linda, CA
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How did you manage to kill a sprag with a LBA? Think of LBA as insurance, not prevention.
The INTERNET, the MISinformation superhighway
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Re: What makes a TH400 stronger than a 727?
[Re: John_Kunkel]
#3228791
04/23/24 03:16 PM
04/23/24 03:16 PM
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Joined: Jan 2022
Posts: 138
Connellsville
71Demon528
member
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member
Joined: Jan 2022
Posts: 138
Connellsville
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How did you manage to kill a sprag with a LBA? Think of LBA as insurance, not prevention. I certainly agree, anything can break especially in a race environment. The LBA is definitely insurance. I was just curious as to how it managed to take out a sprag with the LBA. I have never heard of one doing that so I was curious is all.
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