Renone

Hi Tony. will the th400 set up work if I where going with a LS? I have a 63 starfire 2 door hard top. I just got it about 3 months ago and it has no engine just tyranny.
If not what would you recommend? Thank you.

Olds64

I moved your post to a new thread. The previous thread was about modifying a TH400/TH350 to fit in place of a Slim Jim Rotohydramatic.

If you want to LS swap your Oldsmobile I suggest finding a running vehicle as a donor. Then you can swap the LS and transmission together.

I have coworkers that do this on the side and cut down the OE wiring harness. If you don't want to do that you can always get an aftermarket harness from Summit or Jegs. Heck, Walmart might even carry them now!

Charlie Jones

First, A '63 Starfire did not have a Turbo Hydramatic 400 trans.
It had a Roto Hydramatic 10 trans.
The only engine that will bolt up to it is a '61 thru '64 394.
If you are bent on an LS engine, use whatever trans came with it.
Be aware that major floor pan surgery will be required to accommodate this swap.

BangScreech4-4-2

If it indeed has a Slim Jim, you're best off locating an appropriate 394 unless you want to disappear down a modification rabbithole and most likely end up with an abandoned project.

Not saying that's what will happen to you, but I see it all too often.

Renone

Thank guys but my question was for someone in a different form but it got moved here. So yes my 63 has the slim jim tranny that probably don't work. No engine as well. I'm question was for Tony at Ross Racing. I wanted to see if a LS with a th400 would work without having to cut the transmission tunnel. If anyone has done this combo any info will help.
Thanks.

Olds64

You can try to PM @Ross Racing Engines He hasn't been active on our site in 5 years.

No, the TH400 won't fit in place of a Slim Jim without major floor pan surgery. I seem to recall that a 4l60 also requires modification to the floor pan.

Renone

Thanks OLDS64. I'm have to try that . Apparently Ross has a th400 ( that's probably modified) that will work with out doing any cutting. I would love to run the 4l60e but I know it requires cutting along with any other tranns that's not a slim jim. Thank guys.

Olds64

I also suggest you PM @KQQLCAT He was last active in April.

BangScreech4-4-2

If you search, there are several threads on here about adapting a TH400 for your application in a vehicle that had an existing 394. In all cases some degree of floorpan surgery was necessary. Can't comment on incorporating the transmission change into an LS swap as that throws a bit of a wildcard into things.

If you need to talk to Tony, it's probably best to contact him through Ross Racing. Although I suspect LS swaps into early '60s B or C-bodies are a bit outside of his wheelhouse.

KQQLCAT

I put a TH400 in my 61 Olds and didn't have to cut the floor. I would think that this can be done because the LS is smaller than a 394. Since you have to make new motor and tranny mounts you could bump the engine forward an inch and that would give you a lot more room.
Pat

Olds64

Thanks for the info Pat. Didn't know a TH400 would fit without floor pan surgery.

Renone

KQQLCAT did you have to do anything to the th400 outer casing? or did it slide right in. The th400 will mount to the LS with a couple of new parts. If the th400 will slide right in without major cutting then, I think thats the plain for my built. Thanks

KQQLCAT

Look at this thread: My New TH400 Compared To Slim Jim

Olds64

Here's the link:
https://classicoldsmobile.com/forums...lim-jim-17372/

70ish

So i just put in a LS2 w/ T56 in my 70 cutlass and did have to alter the tunnel. But stating that, Holley has newer oil pans for the LS that give you more room to push the engine/trans forward (would also depend on the motor mount). you might be able to get away without surgery but it would really depend on the type of tranny & mount. i would go with something with overdrive (4l60 or 200r4 or equivalent) for comfort and efficiency. I used Holley 302-1 pan and BHP mount combo and can share more info if desired. Ed