roadmaster and impala driveshaft?

[bob94]

are they the same length? the roadmaster had rear drum brakes, but has a lt1. doing a rearend swap on my l99 1994 caprice. my driveshaft is too long. navy said i needed one from a 9c1 or impala (driveshaft). i have one from a roadie. will it work...

[305classic]

no, it must be from a 9c1 or impala. i don't have a reason other than there shorter but it is a must unless you send your driveshaft out to be cut shorter.

[bob94]

kinda figure that... well let the hunting begin... thanks 305...

[305classic]

did you get a rear end from a 9c1 or impala?

[Navy Lifer]

Originally Posted by 305classic

no, it must be from a 9c1 or impala. i don't have a reason other than there shorter but it is a must unless you send your driveshaft out to be cut shorter.

Driveshaft for any 94-96 sedan or wagon with LT1/8.5" will be the same length--L99 with 8.5, too.

Not sure about 91-93 cars.

[305classic]

from what i was told, the 9c1 and the impala have a shorter driveshaft than any of the other b-bodys including the L99 caprice.

[Navy Lifer]

I'll spell it out another way....

All 91-96 B-body cars are the same wheelbase.

1994 thru 1996 used the 4L60E transmission, and either an 8.5" ring gear axle or a 7.625" ring gear axle.

Any 94-96 car with 8.5" axle, regardless of engine, has the SAME length (shorter @ 54.59") driveshaft. There are different versions of the "short" shaft, with special balancing for the Impala SS & 9C1 because these cars were built for higher speed capability--ie. higher driveshaft RPM.

The driveshaft for the 8.5" axle is SHORTER because the larger ring gear diameter moves the pinion forward, which means the distance that the driveshaft has to "fill" from the back of the transmission to the pinion flange on the differential is less.

Any 94-96 car, regardless of engine, with 7.625" axle, uses a different (longer) driveshaft than cars with 8.5" axle--for the opposite reason.

Leaving 91-93 out of the discussion, since they used different versions of transmission which could result in different driveshaft specs. Have not checked to see if they are same or different.

Whatever you were told, this is the complete story.