midwestjunk

iTrader: (2)

pulled my t-56 out. looking to put a th400 in. I am clueless w automatics. i know autos use a flex plate, now do i use a LS1 flexplate for a th400 or do i need some special conversion one? cant I just use a ls1 flexplate and have a convertor company make me a convertor that works for th400 mated to ls1 flex plate?

so far I got a th400 short tail lined up
-jw ultra bell
-shifter
-custom driveshaft
-UMI trans crossmember

I know i need a flex palte and convertor but thats where i'm confused.

what other parts will I need?

midwestjunk

iTrader: (2)

bump.

bodies67

Gm makes a conversion to put a turbo 350/400 to a ls motor. I can't remember the part#. I saw it at scoggin dickey web site. It came with everything to change it over to mount the bellhousing to the ls with some spacers for the flex plate.Check there web site.

MUSTANGBRKR02

iTrader: (91)

Go with a SFI rated TCI or similar flex plate. You are going to need a dipstick which I would get the Madman dipstick over a flexible Lokar one.

Duffster

iTrader: (103)

You can use the flex plate from a 6.0L too. Thats what I did. I was considering offering you a trade a few days ago for my TH400 for your T56, but I procrastinated and see now you've got most of it going on. Check out the thread on making the speedo work... VERY useful!!!

tt383lt1

iTrader: (3)

uses a ls1 flex plate a sertifed one with the same bolt paterns to you torqe convertor bolts and a th400 tranny mount. a new driveshaft or modify yours. mad mans dipstick. shifter with cable and are you plan on running stock speedo you need a speed sensor and reculor wheel for the tail housing of the th400 and pig tails. and a tranny cooler. im pretty sure thats it

Cam72aro

iTrader: (28)

Dude, Do some searching. There is about 300 th400 build threads on here.

MUSTANGBRKR02

iTrader: (91)

You do not need all of that to make the speedo work.

You can tap the ABS sensor to run the speedo.

tt383lt1

iTrader: (3)

thats sweet i never heard of that befor. i use a vss setup. how would you do that?

Duffster

iTrader: (103)

tap the front or rear ABS wires/sensor and adjust the PCM . . .

https://ls1tech.com/forums/automatic...350-th400.html Page 2 close to the end is most useful

Cam72aro

iTrader: (28)

Look down two threads and it tells you how to do it.

midwestjunk

iTrader: (2)

i didnt buy the trans or parts yet. my t-56 sold today and i was gonna go buy the trans and parts monday. pm me with what you have. i have cash just sitting her from my trans that sold.

Duffster

iTrader: (103)

If I sold my parts, I couldn't drive... hence the thoughts of swap. Sorry.

MUSTANGBRKR02

iTrader: (91)

That's the one.

midwestjunk

iTrader: (2)

anyone have experience with the YANK flex plate? I see its only $80! and SFI rated or whatever. seems like a nice piece.

MUSTANGBRKR02

iTrader: (91)

It's a C.A.T. Flexplate that used to sell for like half of that but I would go with a quality piece the first time. My CAT one cracked just like the stock one.

los p

iTrader: (2)

so with the tci flexplate do u still need the spacer or u need the spacer with any flexplate, thats where im confused?

midwestjunk

iTrader: (2)

what i have found is you run a ls1 flexplate. then you tell the convertor company to custom make you a th400 to a ls1 convertor. the snout and bolt pattern will match a ls1 convertor. so then it becomes a direct fit. if you use a SBC convertor you need a spacer or adapter.

MUSTANGBRKR02

iTrader: (91)

TCI unit comes with the spacer needed then you just use a regular converter.

StraightTimeStirrups

Next time, copy and paste a link to the thread as they tend to move up and down as people post! Doing searches are not the easiest way to find them. I am looking to do a conversion from t56 to TH400 myself on a 1993 Trans Am and I havent found squat on the conversion no matter how many ways I ask the Search function!

Joe