[sdbob]

Has anyone used a long tail shaft m40 in 63 Tem pest or 70 Fbody? Why? I had one completely overhauled when I had my Granville. So its sitting. Thought I could use it. I'm thinking though the driveshaft angle would be too steep.

[tom s]

Could present a drive shaft angle problem with the short wheel base?Tom

[Joe's Garage]

Have a transmission shop / guy swap out all your new stuff into a short tail T400.

Problem solved.

Just a thought.

[b-man]

I did that once with a ‘76 T/A.

Put in a good used long tail TH400 and had the driveshaft shortened and modified the transmission crossmember (moved the mount to the rear side). Low on dough and had time to modify stuff, I needed a car to commute in.

After a while it seemed that the output shaft bushing was taking a beating. Granted it might’ve already been worn some but I don’t doubt the driveshaft angle had a part in it. Did have a bit of a vibration at highway speeds too, been too many years but I do recall thinking I would’ve been better off with a short tail TH400.

There’s probably a pretty good reason the factory had a few different tail shaft lengths for the various different chassis configurations.

However many of us are adapting longer automatic overdrives and even additional overdrive units that require a shorter driveshaft.

It will work, but of course the short tail is really a much better way to go.

[4zpeed]

Originally Posted by b-man

There’s probably a pretty good reason the factory had a few different tail shaft lengths for the various different chassis configurations.

A long-tail version of the Muncie was produced to shorten drive shaft length in longer wheelbase cars.

It was a effort to reduce harmonic vibration, the M40 long-tail most likely served a similar purpose.

Muncie long-tail drivers-side speedo
Casting 384362 (Rare)


Muncie Catalina long-tail pass-side-speedo
Casting 9779246




Frank

[sdbob]

Thanks for the info. I thought the angle would be too sharp. I have extra short shaft and housing. I'll just switch. Yep when I was younger I also would try most anything. Without guidance you say let's try what can it hurt. Also being young you had time!!

[67Fbird]

and yet know we have the input from thousands who probably have never actually tried much of anything.....lol
young, dumb, and skint knuckles......teaches ALOT once you understand WHAT you are learning..

[sdbob]

I remember my first BW 4spd in my 63 GP.The countershaft bearings rolling around my buddies garage floor! what the heck did I get myself into!

[Tom Vaught]

The length of the driveshaft DOES make a difference in driveshaft harmonics on longer vehicles.

Ford had a problem for many years with a vibration from incorrect drive shaft angles. It was worst on Conversion/ Airport vans due to the added weight and vehicle length and usually showed up when they were about six months old after the springs had settled a little and were traveling at high vehicle speeds.

The Airport Drivers for a while were playing a game where they would show up at the Airport Taxi pick-up location late and then because several people always thought they would miss their flights, would offer to make the flights (IF the travelers would help pay the ticket if he was stopped). He would then travel to the airport at 100 mph to get there for the flights. In some cases the vibration at that speed was enough to fail some driveshafts.

Ford stopped that crap by limiting the vehicle speed to 89 MPH on the vans.
Below the critical driveshaft speed.

You can't just swap that stuff around and assume you are safe at high speeds.
Running at 70 mph, might live forever.

Tom V

[Hikin Mike]

Been using a long shaft TH400 in my 69 Firebird since I've owned it (1988).

[Tom Vaught]

Shorter vehicles like Firebirds and 63 Tempests, Hum.

Wonder why Tom S had comments about the trans installation on his tempest and you have had no issues since 1988?

Our issues were mostly with too long of a driveshaft. Not the driveshaft angle.

So SDbob, here is a member who has been running one since 1988.

Tom V.

[Sirrotica]

Since the long tail transmissions are way more plentiful than the short versions I've used them in everything from A bodies to F bodies without any repercussions for many years. I used them in A Body 87 GTO dirt cars, 68 Lemans street car, 73 Grand Am street car, 2, 76 TAs. From my experience I wouldn't have any worries about running a long tail transmission in an A or F body, nor a 63 Tempest. The early altered wheelbase funny cars used the long T 400 because GM didn't start making the short tail version until 1967.

FWIW, not all GM B bodys used the long tail T 400 either, Buick used the short tail version in their B bodies in 67-69.

If you have any worries about drive shaft angles perhaps you've never spent much time under a Jeep. Not only are Jeep driveshafts at steep angles they also are offset from side to side many times. The shortest wheelbase on the early CJ5 is 81 inches, over 2 feet shorter than a GM F body.

Consider that Jeeps were also geared much lower (4.10-4.56-4.88) than most any GM A, or F, body so the driveshaft RPM is also greater than the average GM muscle car, further compounding the possibility of balance or driveshaft angle problems.

My father used to own CJ5s and I used to do my best to break his Jeep (16 YO), never had any problems with the driveshafts, or U joints.

Bob, if it were my decision I'd use it, and not worry about it, but you own the car, so it's entirely up to your discretion.

[Hikin Mike]

Originally Posted by Tom Vaught

Shorter vehicles like Firebirds and 63 Tempests, Hum.

Wonder why Tom S had comments about the trans installation on his tempest and you have had no issues since 1988?

Our issues were mostly with too long of a driveshaft. Not the driveshaft angle.

So SDbob, here is a member who has been running one since 1988.

Tom V.

I forgot to mention that my car was in pieces when I bought it and missing a driveshaft. I had to find one suitable. I also didn't know there were two sizes of TH400.

[4zpeed]

Originally Posted by Hikin Mike

I forgot to mention that my car was in pieces when I bought it and missing a driveshaft. I had to find one suitable. I also didn't know there were two sizes of TH400.

Be interested in knowing what you found that worked, in my experience we went from a Muncie to M40 long-tail which required a oddball shaft like your situation.

Couldn't find anything readily available since it was a Olds A body, so we cloned a shaft and had it balanced. Can't recall having issues with vibration, even at speed.



Frank

[Hikin Mike]

Originally Posted by 4zpeed

Be interested in knowing what you found that worked, in my experience we went from a Muncie to M40 long-tail which required a oddball shaft like your situation.

Couldn't find anything readily available since it was a Olds A body, so we cloned a shaft and had it balanced. Can't recall having issues with vibration, even at speed.



Frank

Well, it was 30 years ago. Pretty sure I went to the local salvage yard and told him how big of a drive shaft I needed and he found one.

[4zpeed]

Originally Posted by Hikin Mike

Well, it was 30 years ago. Pretty sure I went to the local salvage yard and told him how big of a drive shaft I needed and he found one.

Thanks Mike, thought the info may be of use to others, over thirty years since my endeavor as well.



Frank

[sdbob]

Thanks guys.

[JSchmitz]

I ran a long tail shaft trans in a '65 Chevelle for many years with no problem. At the time I had no clue about drivetrain angles. I'd rather be lucky than good any day! Lol!