TH-400 trany ?
Thread Starter
Racer
Joined: Jul 2002
Posts: 447
Likes: 0
From: Malta Europe
TH-400 trany ?
hello , I usually hang at the C4 forum ,but I have a question that I think that the C3 people will answer me better ,becouse it is about a TH400 trany to put in my 88 C4 !! I was thinking by making my vette with a th400 instead of the th700 , and I would like to know what is the best gear ratio for a TH400 ,beacuse the 400 is with 3speed hi gears and the 700 is with 4speed lo gears and I was wondering that rear end with 4:10 is good ??? any of you runing 4:10 gears with a TH400 and how you like it !!??
thank you :grouphug:
thank you :grouphug:
Team Owner
Joined: Feb 2003
Posts: 30,183
Likes: 313
From: Lake Norman NC
Re: TH-400 trany ? (marlon88)
i had a chevelle SS396 with a TH400 and 4:10 gears...it sucked gas thats for sure..but it also ran low 8s in the 1/8 mile track near where i live....i later on stripped the gears doing too many burn outs, and put in a richmond 3:42. the 3:42 was good..i still ran in the 8s, but i had to go with 12.5" slicks in the rear, and i could get away with driving down the interstate at a reasonable rpm. i couldn't do that with the 4:10. i guess it depends on how much hp and torque you have.
Safety Car
Joined: Jun 2001
Posts: 4,004
Likes: 2
From: Severna Park Md
Re: TH-400 trany ? (marlon88)
A th400 with 4.10 rear is gonna suck on the highway. It will be strong but the TH400 is also heavy and robs more power from the drivetrain. Most people toss the 400 and go with 2004R or 700R4. Since you already have the 700, why dont you just stick with that? The only advantage I could see with swapping to a th400 in yur case would be if you have a dragrace only car that has a very very powerfull engine(500hp+), and needed the strength of the 400. I would recomend beefing up the 700. It can be done right.
Pro
Joined: Feb 1999
Posts: 666
Likes: 0
From: Memphis,TN
Re: TH-400 trany ? (marlon88)
Hey Marlin,
Got them old -" 700 a'Ren't 4 "- blues ,eh? :(
Join the NOT very exclusive club,bud.
But putting the old venerable T400 in there is NOT simple.
It is NOT even remotely complicated, it is a re-engineering feat.
Your C4 has no crossmember,it uses a connecting beam and some huge bolts to hold the trans to the diff.
Some guys have done it with said Automatic. But there is no "kit" to simply
purchase and install.These were sort of with competition intent,more than street application.
Then there is the speedometer drive to the "Cartoon" dash your car has.
Some systems exist to create a new signa and then recalibrate to suit.
Then of course there is driveshaft issues, the shift linkage,etc. etc.
The considerable help and some links to them are around, and if you think
that this is something you JUST HAVE TO do, I'm sure some of us will direct you there.
The C4 guys I think are MUCH more up on this subject than you infer though.
They of course have MUCH more experience with the 700aRen't 4 Blues than the majority of C3'ers.
http://www.bowtye8.tzo.com I think that link may help.
Good hunting!
Got them old -" 700 a'Ren't 4 "- blues ,eh? :(
Join the NOT very exclusive club,bud.
But putting the old venerable T400 in there is NOT simple.
It is NOT even remotely complicated, it is a re-engineering feat.
Your C4 has no crossmember,it uses a connecting beam and some huge bolts to hold the trans to the diff.
Some guys have done it with said Automatic. But there is no "kit" to simply
purchase and install.These were sort of with competition intent,more than street application.
Then there is the speedometer drive to the "Cartoon" dash your car has.
Some systems exist to create a new signa and then recalibrate to suit.
Then of course there is driveshaft issues, the shift linkage,etc. etc.
The considerable help and some links to them are around, and if you think
that this is something you JUST HAVE TO do, I'm sure some of us will direct you there.
The C4 guys I think are MUCH more up on this subject than you infer though.
They of course have MUCH more experience with the 700aRen't 4 Blues than the majority of C3'ers.
http://www.bowtye8.tzo.com I think that link may help.
Good hunting!
Thread Starter
Racer
Joined: Jul 2002
Posts: 447
Likes: 0
From: Malta Europe
Re: TH-400 trany ? (marlon88)
thanks for the replys !! I am already doing research about all the things that I have to do !! the driveline support beam ,the speedo calibiration and the drive shaft is covered and already planed what to do !! but the rear end ratio is the next factor !! right now I have a dana 44 rear end with 3:54 ratio ,taken from a ZR-1 !! and as far as the future comes , I would like to do a killer 427 small block combo and the 700r4 has to go ,as I already fried it once !!! so gues that the 3:54 is perfect for the TH400 !!
also my vette is going to be a street car but sometimes will see the harch racing envirement because I am a quarter mile fanatik !! :cheers:
also my vette is going to be a street car but sometimes will see the harch racing envirement because I am a quarter mile fanatik !! :cheers:
Safety Car
Joined: Aug 2001
Posts: 3,685
Likes: 202
From: Waterford Mi
Re: TH-400 trany ? (Schmucker)
To answer your question as to what gear works well with the TH400. Most Vettes came with 3.08 highway gears. I changed to a 3.55. My rpm's whent from 2800@70mph to 32000. I am in the middle of putting the BTO 200R4 in. They say rpm's will drop to around 24500 but the low end gearing will make it seem like I put in 3.9 gears compared with the TH400.
