LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Switching from a 4L60e to TH400

Old 11-24-2008, 11:07 AM
  #1  
Launching!
Thread Starter
iTrader: (16)
 
harner's Avatar
 
Join Date: Jul 2007
Location: New Ringgold, PA
Posts: 236
Received 2 Likes on 2 Posts

Default Switching from a 4L60e to TH400

My TA has about 80k on it, and the 4L60e is shifting fine, but I'm getting an LT1 block bored and gathering quite a long list of internals and whatnot. Needless to say, I need something a little more stout for the street and a dozen passes at the track a year and low cost/maintenance.

So, i decided to go with a turbo 400 and possibly a manual valvebody. I can get a core for dirt cheap, I just need to know what to ask for. A buddy told me he has a short tail (6") turbo 350 in his 84 Firebird, so I'm guessing a 6" tail would be the correct kind to look for?

After some research, this looks to be what I need to look for:
TH400
Shifter
Stall
Crossmember
Flexplate?

Will the shifter linkage, pedal assembly, etc all work? Also, will it bolt right up to an LT1?

Thanks!

Last edited by harner; 11-24-2008 at 12:17 PM.
Old 11-24-2008, 11:16 AM
  #2  
TECH Fanatic
iTrader: (12)
 
Black94Z28's Avatar
 
Join Date: Aug 2007
Location: Cornfields near Pontiac, IL
Posts: 1,818
Likes: 0
Received 1 Like on 1 Post
Default

Make sure you get a chevy th400 trans. buick olds pontiacs th400s had different bolt patterns
Old 11-24-2008, 11:29 AM
  #3  
11 Second Club
iTrader: (88)
 
the_merv's Avatar
 
Join Date: Mar 2006
Location: The Beach...
Posts: 19,250
Received 58 Likes on 51 Posts

Default

I don't see why your Flexplate from the LT1 wouldn't work..

Flywheel is for Standards..
Old 11-24-2008, 12:17 PM
  #4  
Launching!
Thread Starter
iTrader: (16)
 
harner's Avatar
 
Join Date: Jul 2007
Location: New Ringgold, PA
Posts: 236
Received 2 Likes on 2 Posts

Default

Originally Posted by the_merv
I don't see why your Flexplate from the LT1 wouldn't work..

Flywheel is for Standards..
Fixed lol
Old 11-25-2008, 07:37 AM
  #5  
Launching!
Thread Starter
iTrader: (16)
 
harner's Avatar
 
Join Date: Jul 2007
Location: New Ringgold, PA
Posts: 236
Received 2 Likes on 2 Posts

Default

So a Chevy TH400 short tail? What about the driveshaft? Will a regular one fit or will I have to get a custom one?

Do one of the sponsors sell them for Turbo 400 conversions?
Old 11-25-2008, 07:44 AM
  #6  
Banned
iTrader: (22)
 
LS1 SPEED's Avatar
 
Join Date: Jan 2004
Location: Schaumburg,IL
Posts: 4,957
Likes: 0
Received 0 Likes on 0 Posts
Default

We can help you put together a TH400 setup, but unless you are going to be making 700+ HP build your 4L60E.

I'm running a FLT level 4 in my own car and my customers cars which go or will go 9's. The are cars which are driven on a regular basis too. I pulled my TH350 so the car was much more enjoyable to drive on the street and hwy.



think about it hard before you commit to the swap
Old 11-25-2008, 08:47 AM
  #7  
Launching!
Thread Starter
iTrader: (16)
 
harner's Avatar
 
Join Date: Jul 2007
Location: New Ringgold, PA
Posts: 236
Received 2 Likes on 2 Posts

Default

I was planning on up to 550hp at the motor. I've just heard so many horror stories with the 4l60e, and the thought of a manual valvebody is cool Plus the cost of having it built is much cheaper around here.

Whats the weight different between a 400 and 4l60e?
Old 11-25-2008, 09:21 AM
  #8  
Banned
iTrader: (22)
 
LS1 SPEED's Avatar
 
Join Date: Jan 2004
Location: Schaumburg,IL
Posts: 4,957
Likes: 0
Received 0 Likes on 0 Posts
Default

not sure of the weight difference, but coming from 2 cars with 3 speeds it really takes away from the street driving.

I would never have a TH400 in a car unless it was mainly a track car making huge power.

it sucks when everyone else is flying down to HWY and here you are stuck at 55 mph

Turbo cars require small gears and a 28", so they are more forgiving on the street with a TH400/TH350

cost...yes there is a big difference in cost, but keep in mid your enjoyment.

FLT is my choice since we have had great success and have used no others


Thread Tools
Search this Thread
Quick Reply: Switching from a 4L60e to TH400



All times are GMT -5. The time now is 06:57 AM.