TH-400 case

pldmalibumalibu

Amateur Racer
Oct 7, 2009
288
0
0
The 508
I was told that the 6 bolt case I have will not be good for a perfomance rebuild . Do I need to go find a 8 bolt case now ? The trans I have now has HD 46 cast into the bellhousing and the front pump has the 895 on it.
 

1981Regal

Dragway Regular
Mar 10, 2008
1,274
0
0
Cincinnati, Ohio
They might be referring to the 4L80E but the th400 should be fine. Far as I recall all the th400s have a 6 bolt tailshaft housing.
 
We have not found any significant power limitations (within reason) to the 6-bolt TH400 transmission case. We have a customer with a 3,000 pound drag radial car equipped with an alcohol EFI 632 and an F-3R 136 ProCharger utilizing a 6-bolt TH400 case without any issues. Another customer of ours runs a 6-bolt case behind his 498 DRCE II combination that turns upwards of 10,200 RPM, and, again, has had no issues.

We do prefer to use an 8-bolt case when we're building a unit for use with a JW Ultrabell simply because having the extra two bolts in there provides an even stronger joint between the bellhousing and case, but we've used JW bellhousings on 6-bolt cases without any problems as well.
 

pldmalibumalibu

Amateur Racer
Oct 7, 2009
288
0
0
The 508
We have not found any significant power limitations (within reason) to the 6-bolt TH400 transmission case. We have a customer with a 3,000 pound drag radial car equipped with an alcohol EFI 632 and an F-3R 136 ProCharger utilizing a 6-bolt TH400 case without any issues. Another customer of ours runs a 6-bolt case behind his 498 DRCE II combination that turns upwards of 10,200 RPM, and, again, has had no issues.

We do prefer to use an 8-bolt case when we're building a unit for use with a JW Ultrabell simply because having the extra two bolts in there provides an even stronger joint between the bellhousing and case, but we've used JW bellhousings on 6-bolt cases without any problems as well.
Thanks for the info. I have a 78 Malibu that weighs 3600 lbs with the driver .Its got a F1a ProCharged 468 Big-Block . Stepping up to a TH-400 & a 9''rearend so I can turn up the boost. I was curious about the case because I had never heard of people shying away from the 6 bolt cases. The car goes 10.02 now with a TH350 & a 8.5 GN rearend but the trans let go at the end of the season so Im doing it all at once so im not cutting the driveshaft more than once. I run Radial -Pros & will be using a trans-brake.
 
pldmalibumalibu said:
Thanks for the info. I have a 78 Malibu that weighs 3600 lbs with the driver .Its got a F1a ProCharged 468 Big-Block . Stepping up to a TH-400 & a 9''rearend so I can turn up the boost. I was curious about the case because I had never heard of people shying away from the 6 bolt cases. The car goes 10.02 now with a TH350 & a 8.5 GN rearend but the trans let go at the end of the season so Im doing it all at once so im not cutting the driveshaft more than once. I run Radial -Pros & will be using a trans-brake.
No issues at all with a 6-bolt case in that combination. You have nothing to fear. Whoever is telling you to avoid that case is providing incorrect information.
 
Thread starter Similar threads Forum Replies Date
B drivetrain help turbo 400 Transmission Technical 2
D Small block Chevy 400 engine with different pistons in it ?? Drivetrain Technical 2
D SBC 400 COMPRESSION RATIO? ?'S Drivetrain Technical 1
D What cam for stock SBC 400 engine????'s Drivetrain Technical 9
thumper 2004r or 400 Transmission Technical 4
D Best Intake and Carb for SBC 400 engine???'s Drivetrain Technical 11
G-boz TH-400 "Ears" Transmission Technical 14
CFH87 400 sbc build Drivetrain Technical 7
lilbowtie T-400 locks up in third Drivetrain Technical 4
H th 400 crossmember Transmission Technical 12
D SBC 400 HEADGASKETS???'S Drivetrain Technical 1
D SBC 400 headgaskets ???'s Drivetrain Technical 1
S T 400 mount proob Transmission Technical 3
G 400 trans rebuild Transmission Technical 3
D SBC 400 block value???'s Drivetrain Technical 2
D SBC 400 LEAKING REAR MAIN SEAL ???'S Drivetrain Technical 8
D SBC 400 .60 OVER ???"S Drivetrain Technical 1
D SBC 400 .60 OVER ???"S Drivetrain Technical 13
D Oil Leak on SBC 400 engine???'s Drivetrain Technical 6
M 400 turbo dipstick Transmission Technical 3
footbrake Burnout with a 400 Transmission Technical 17
R 400 trans in 79 El Camino Drivetrain Technical 20
8 350 or 400 Drivetrain Technical 11
Brian79 sbc 400 casting, which is best? Drivetrain Technical 13
N whats the max i can do with a 400 block? Drivetrain Technical 5
P factory 400 block Drivetrain Technical 27
A ? +60 400 sbc Drivetrain Technical 10
jitteryguy SB 400 Drivetrain Technical 3
A th 400 problems Drivetrain Technical 6
A BIG BLOCK/TURBO 400 TRANS Transmission Technical 3
Deuce4935 Th-400/Lt1 Transmission Technical 1
L turbo 400 or 2004r to lq4 LSx Tech 3
B 400 small block wich way to go Drivetrain Technical 6
D 4L60/4L60E case fittings... are they the same? Transmission Technical 2
D GM techs (or anyone else that may know) - 4wd t-case ? Transmission Technical 15
wiseman79 In case anybodies looking... LSx Tech 0