Is drive shaft to short ?

[Boss 351 cobra]

I am putting different moter and trans in my Cobra.The motor is almost 2 inches offset from rear end.The driveshaft used to be 11 inches from u joint to u joint, The new drive shaft will only be 6 inches from u joint to u joint. Is this short shaft going to be to be a problem

[Bob Putnam]

Boss,

Your angle (~18 degrees) is on the limit of some flanges, so I would check for interference between the adjacent parts. The high angle decreases the joint rating somewhat, but I don't think it will be a problem. Just in case, I would use a driveshaft strap or equivalent to deep a broken u-joint from breaking one of your body's joints...

Because there'll be quite a bit of extra heat generated, keep a close eye on the joint lubrication. Initiallly, I'd check it every 1000 miles. If it doesn't look like you're throwing a lot of grease, you can increase the paranoia interval.

[Mr.Fixit]

If you don't have an IRS, than any up/donw movement of your rearend will cause huge changes in the U-joint angles.

[Bob Putnam]

Since every Arntz I've seen has a Jag independant rear, I assumed that he had one too.

[Monster]

Boss 351,

You don't mention what engine/trans. combo you are changing to (not that it should matter much on offset) however, I have a big block and just changed my trans from a toploader to a Tremec. I didn't need to change my driveshaft because I had my Tremec input shaft machined (shortened) to eliminate using an adapter (available from Forte and Modern Driveline). I did have to make a new trans mount.
Now, with that said, I can measure my driveshaft, but I'm sure that it is longer than 6" (probably 8"- 9" U-Joint-U-Joint). As for being offset by 2", that sounds like alot ( are you talking lateral or vertical offset? . I can put my car in the air and measure if that would help you out.

Let me know,
Mike