Will a TH400 Transmission bolt to a 394?

[Oldsmobile]

I have a 1963 Oldsmobile Starfire with the "Slim Jim" transmission. I am trying to figure out if anyone knows whether a 400 Turbo-Hydramatic will bolt onto that engine without any problems.

Thanks.

[Oldsfan]

You can bolt a 400 to that 394, but you have to send the case to a place in California to have it machined to fit, then you have to put the guts back in it. Then there is the issue of floor clearance. And the shifter quadrant. And throttle linkage. If I haven't discouraged you, I can come up with the name of the place.

I gave all of this some thought a year ago. Haven't given up yet. Actually, my buddy suggested a 700R4 to get the overdrive, and then I could go back to my stock 3.42 gears.

Paul

[joe_padavano]

Actually, there's an adapter kit available now:

http://www.transmissionadapters.com/Pricing.htm

[Oldsfan]

Wow. That is great information. Looks better than the conversion I was previously considering. I still wonder about floor clearance and linkage/shifter issues. They don't mention transmission/rear engine mounting.

What d'ya say, Glenn? You do yours first and let me know how it goes...

Paul

[Oldsfan]

Here is the link for the previous conversion I was considering:

http://www.forwhatyouneed.com/transmission%20adapters,%20conversion.htm

Paul

[rocketraider]

I think the Bendtsen kit will probably work good up thru 62 as they seem to have a little more engine to firewall clearance than 63 and especially 64. I'm thinking you'd almost have to weld in a 65-later trans tunnel to get clearance for a 350 or 400 transmission. Not sure on a 200 or 700. Not an issue on a 64 console car as 64-66 all use the same console except the shift indicator.

Upsides- NO MORE SLIM JIM ANTICS! Meaning you can also ditch the 4GC, and almost anyone can rebuild the trans down the road. Plus early Rocket torque thru a modern transmission ought to be a blast. Throttle linkage should be as simple as a Lokar cable kit, but I'm sure the original carb linkage would work fine once the TV rod is out of the way.

Downsides- by the time you've bought the kit, a transmission and rebuild, and modified the floor, you could have rebuilt the Slim Jim. And that's assuming your Rocket engine doesn't need a rebuild at the same time.

Me, I kinda like the idea of that stick kit! Figure out pedals and a hydraulic clutch and you're set. There's still plenty of junker F/S stick Chevys around from that timeframe, and I expect the pedals could be adapted to another B-body car easy enough.

[Oldsmobile]

Glenn, my slim jim transmission is strong - not in need of rebuild. I putting a 3/4 race came in my 394, as well as an offenhauser dual quad intake, solid lifters, and having the heads polished/ported. My fear is that the slim jim will not perform as well with the additional horsepower and that's why I was thing TH400 transmission. Perhaps I'm wrong, perhaps the slim jim is just the ticket?

[Guest rocket88coupe]

if u have a strong slim jim u b lucky,they were known to just quit with no warning,im running a 394 cam 3x2s jahns 10-1 forged pistons,internaly balanced thru a early hydro,that way i could get 4 speeds and they just dont know how to break ,have had no probs with it it shifts real hard where the slim jim and jetaways slipped a little going in each gear takes a little scrounging for parts and a little work but bolts right up to the 394 (keep your motor mounts too)

[junkyardjeff]

A 59 or 60 jetaway trans might work if it will fit the trans tunnel,they shifted a little wimpy compared to the 56 on back hydro but I had one in a 53 behind a 59 371 with no problems. Jeff

[Guest RUSTYROCKET88]

if u have a strong slim jim u b lucky,they were known to just quit with no warning,im running a 394 cam 3x2s jahns 10-1 forged pistons,internaly balanced thru a early hydro,that way i could get 4 speeds and they just dont know how to break ,have had no probs with it it shifts real hard where the slim jim and jetaways slipped a little going in each gear takes a little scrounging for parts and a little work but bolts right up to the 394 (keep your motor mounts toI know this is a REALLY old post.  I am wondering what transmission (and parts) you have (had) bolted to your 394?

I know this is a REALLY old post, But I am wondering what transmission you have (had) "bolted right up" to your 394 ???

[rocketraider]

As stated earlier nothing bolts to an early Rocket but a pre-65 HydraMatic. They have an adapter plate that bolts to the engine block then the trans bolts to the adapter.

 

The folks in CA Oldsfan mentioned have been doing THM conversions for 49-64 Rocket for a looong time and Ross Racing Engines in OH also modifies THM to bolt to these engines.

 

Over on classicoldsmobile.com, a poster named KQQLCAT had a great build thread on using the RRE kit in a 61 Dynamic 88, and someone else (can't remember who) had one on putting 700R4 in 63 Starfire. Reading thru those might give you a good idea what you're going to get into.

 

But yes, I'd consider a 200-4R or a 700 to get OD especially if you have a Starfire with their 3.42 gearing.

[Guest rocket88coupe]

I know this is a REALLY old post, But I am wondering what transmission you have (had) "bolted right up" to your 394 ???

right now as i enter my trilight years,its a 59 jetaway as i dont really care for the harsh shifts that i had with the slant pan kinda feels like a old buick dynaflow,not for dragging the main for sure but sat night cruises going to car shows hard to beat,for your other questions e-mail me rocket88coupe@aol,com