turbo 400 - strength - recommended upgrades? - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Transmission - Rearend
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 01-16-2005, 02:42 PM
fearsomefairmont's Avatar
Member
 
Join Date: Mar 2004
Location: wisconsin
Age: 30
Posts: 102
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
turbo 400 - strength - recommended upgrades?

Howdy Folks,
Being mostly a Ford guy, I was looking for some info regarding the TH-400 in a '72 Olds Cutlass (455 big block) I just purchased.
To me, the TH-400 seems similar to a Ford C6 as a TH-350 would be a C4.

The car drives fine but seems soggy. The last time I drove it, it developed a fluid leak from the cooler lines so I parked it immediately after driving about 2 blocks.

The motor is as follows: mild ported iron heads, hydro cam w/ .475 lift and 230@.050 duration, Edel. performer intake, Edel. 800 cfm carb, long tube headers, dual exhaust. 9:1 compression. Rear-end is B.O.P. 10-bolt w/posi. I estimate around ~300 hp, but at least 450 ft/lbs torque.

Do you think 2 blocks with poor fluid pressure burnt the clutches? Any mods to be done to the tranny? I am planning on putting in a 2800 rpm stall converter and bigger cooler soon.

Should I get a different valvebody? Would an aggresive shift kit work fine or not? I would just like to put on a shift kit and leave it (CHEAP!).

Let me know your thoughts. This is a mostly street car.

Thanks,
Andy

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 01-16-2005, 06:39 PM
Will I ever get it done?
 

Last journal entry: Exhaust, Filler, and Trailer
Last photo:
Join Date: Oct 2004
Location: Tulsa, OK
Age: 57
Posts: 1,049
Wiki Edits: 0

Thanks: 1
Thanked 3 Times in 3 Posts
IMHO, one of the great things about a Turbo 400 is that you don't have to buy a shift kit to get decent shifts for the street or strip. Leave out 5 of the balls (all 6 if you know which hole to plug in the seperater plate and don't mind no engine braking in 1st). Turn the accumulator piston upside down (throw out the spring - you may have to purchase a "no-leg" accumulator depending on your tranny). Plug the low shift hole and grind off the side of the valve. For the strip, you have to plug a hole in the center support and leave out the middle seal on the clutch piston. A better sprag (34?) would be a good investment for the strip.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 01-16-2005, 08:35 PM
jakeshoe's Avatar
Member
 
Last photo:
Join Date: Dec 2004
Location: Texas
Age: 38
Posts: 613
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
I would recommend against the above mods..

Personally I would install a Transgo reprogramming kit. It will dual feed the direct clutches without tearing into the trans, opens the feed holes for fimer shifts, changes the accumlator valve spring for firmer shifts, and can increase line pressure.

Flipping the accumulator piston can cause failures and some of these mods will cause brutal part throttle shifts. The TransGo kit will have a progressively harder shift with more throttle.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 01-16-2005, 09:02 PM
Will I ever get it done?
 

Last journal entry: Exhaust, Filler, and Trailer
Last photo:
Join Date: Oct 2004
Location: Tulsa, OK
Age: 57
Posts: 1,049
Wiki Edits: 0

Thanks: 1
Thanked 3 Times in 3 Posts
I modified the 400 in my 3800 lb 60 Chevy w/ a 396 during a complete rebuild and I modified the 400 in the 68 Suburban w/ a 454 that I used to tow it. The wagon had over 400 passes on it without any work or failures. I can't remember how many miles I put on the Suburban daily driving, towing, and bracket racing it. My wife probably thought it was a little harsh on the shifts, but it didn't bother me. And no failures. The tow vehicle cost me the price of a 1/4" bolt, an allen bolt (can't remember the size), seperater plate gaskets, pan gasket, filter, and about 4 qts. of tranny fluid.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 01-16-2005, 11:39 PM
jakeshoe's Avatar
Member
 
Last photo:
Join Date: Dec 2004
Location: Texas
Age: 38
Posts: 613
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
I've done the same modifications before I knew better.

It does make it shift hard.

One trans didn't live past the first WOT 1-2 shift behind a mild 427.

Accumulators are designed into a trans for a reason beside just softening up shifts.

Shift timing on a 1-2 upshift, and a 3-2 downshift are critical on a TH400 and Th350.

Get it wrong, and you ruin sprags (yes even HD 34 element ones) and break parts.

The $45-50 for a TransGo kit is well worth the money IMO, as it gives some option as to shift firmness, yet retains the accumulators function, and dual feeding the somewhat weak direct clutches all at the same time.

Lots of ways to get there, lots of ways to break parts.
Most people have no way of knowing what the low exhaust is, or have extra VB gaskets, etc.

Kit is worth the price of admission for a beginner, because of thorough instructions.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 01-17-2005, 01:11 PM
fearsomefairmont's Avatar
Member
 
Join Date: Mar 2004
Location: wisconsin
Age: 30
Posts: 102
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Sounds good

Well, the consensus seems to be just to use the Transgo kit. The price is certainly reasonable.

I will upgrade the sprag to a heavy duty one when I get to putting some Edel. aluminum heads on the motor, I am sure upgrades will be needed as a good olds 455 can put out 550+ ft/lbs of torque.

From what you say, a good shift kit is acceptable. I don't want shifts that rattle my teeth out, so I am going to stay away from other mysterious valvebody mods.

I also just installed a Hurst pistol grip quarter stick on the floor. That is such a *****in' shifter - when you slam it forward its like shooting your opponent.

Thanks for your help -

Andy
Reply With Quote Quick reply to this message

Recent Transmission - Rearend posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -6. The time now is 07:27 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.