[thebrat1967]

Hello friends,
I am wanting to install a TH 400 in my 67 Firebird convertible up to the 326.
I have a 400 but it has a long shaft, will it work with out cutting the drive shaft or just what would be the best option? I'm sure someone has done this before to replace the super turbine 300.
Any input would be appreciated I am also installing the console to replace the column shifter it has now. So I am also looking for a cut pattern for the middle housing for the linkage to go thru.
Thanks for any help, my email is sparky69162@yahoo.com

[Squidward]

My 67 was already converted to a TH350, which is pretty much a drop in.

I am pretty sure the ST300 converter is ST300 only.
Your shifter linkage will need to be adjusted to allow it to get to L. It will work with a stock shifter.
The neutral safety switch is also on the shifter, so that will be something you will have to convert over and make work for a 3 speed.
I think your shift selector shaft works fine.
The crossmember and mount is TH400 specific, but the factory style ones will probably be for a short tailshaft TH400. I will guess you will need to do some fabrication if you are Hell bent on using the long tail unit.
Driveshaft for a short tail TH400 will be 5/8" shorter (49.96 to 49.30"), and will also need a TH400 slip yoke.

I would either do a TH350 (same driveshaft length, slip yoke, and crossmember) or find a short tail TH400 to duplicate a factory setup.

[Geoff]

T400 is overkill for a 326. A lot more work & expense to fit.
If the car had the ST300, then the T350 bolts straight in. ST300 converter also fits T350 & T400.

[ponyakr]

I agree that for a 326, it is too much work & expense.

But, it can be done. When I bought my 1st '68 Bird, to make a Stock class drag car, it had a 3-speed stick. Rules called for a TH400. I'd only had experience with 4-speed Muncie. So, I went to a local junkyard & bought a Pontiac TH400.. It had a long tail. I knew so little at the time, I wasn't even aware that there were short & long tail TH400's.

1st thing that was required was a crossmember to hold it up. The long tail mount was so far back, it required a custom mount. But, back then I said, many times, that you can fix most anything that's made of metal with a torch & welding machine. So, I just made a crossmember with a piece of angle iron. Some call it fabrication. We referred to it as rigging it. "If you can't fix it right, just rig it."

Then, after installing the engine & trans, I took the original driveshaft, along with a TH400 slip yoke, which I'd discovered I needed, to my local welding shop & had it shortened to fit. Yeah, it was just a junkyard trans, "rigged" to fit, but it worked perfectly for a few races in '74 & a whole season in '75. It was my wife's(then girlfriend) first drag car. She won her first 6 races and several others, in '75. The TH400 set-up worked just fine.

By the end of '75, I'd bought several more '68 Birds & discovered the short tail TH400 & correct crossmember & driveshaft for 'em. So, I never used another long tail, til I bought a race ready '74 Ventura, in 2008. It was "rigged" with a long tail TH400, which worked perfectly. I still have that trans, if anybody would like to buy it. If I use it, I'll probably have my trans guy swap out the long tail parts, and make a short tail of it. That's what I did, with the last TH400 he built for me.

Bottom line, I'm with the other guys who say go with a TH350.

[thebrat1967]

I thought the 400 was a better transmission tho

[TedRamAirII]

Think about a 2004r. With overdrive it would get great gas mileage, and a 326 wont/cant break it.
Since you already have a TH400, convert it to a Short Shaft, get a TH400 crossmember and it all bolts in. No funny business. The shifter just needs a hole for the cable.

[Squidward]

Originally Posted by thebrat1967

I thought the 400 was a better transmission tho

More durable, yes. It is also a little heavier, and consumes slightly more horsepower than a TH350 or 2004r. They are slightly easier (IMO) to rebuild than a TH350.

The only way I would use your long shaft 400 is to do what Ted said, and replace the output shaft and tailhousing to convert it to a short version.

If you plan to grow the project into something with significantly more power, than maybe the 400 gives you room for that. But if you plan on staying with a 326, then I would do a TH350. Or maybe a 2004r, even tho I have never put one of those in anything.

[ponyakr]

I wouldn't run a 2004R because of the TV cable.

A TH350 can be set up to run without the kickdown cable. Some rebuilt TH350's come without the cable. Lots of guys have reported running with the cable unhooked, with no problems.

http://nastyz28.com/threads/had-th35...le-hole.20499/

But, although I've never run a 200R4, I've read that the TV cable adjustment & correct function is critical to trans function & survival. Maybe some 200R4 users can explain how to correctly attach & set up the TV cable for proper function.

http://www.cpttransmission.com/tech_tvcable.htm

http://www.hotrod.com/articles/ccrp-...hrottle-valve/

[thebrat1967]

Originally Posted by Geoff

T400 is overkill for a 326. A lot more work & expense to fit.
If the car had the ST300, then the T350 bolts straight in. ST300 converter also fits T350 & T400.

So if I can find a short tail shaft 350 it will bolt right in? My crossmember will not change either?
How about my cooling lines? This is becoming a real pain in the ***
I have the 400 but it is a long shaft
I do appreciate all the help you guys are giveing me
Sparky

[Geoff]

Yup, T350 will bolt right in. Same rear mount, driveshaft, converter, speedo, cooler lines. Very easy. Later FBs had T350s with short extn housing.
You will need new shifter bezel, shift cable. Kits are available.