I need some help with driveshaft length for a 71 GS455. I bought the car less engine and transmission and a lot of other parts. It has a 8.5" rear end. I had a 455 out of a 71 full size car and found a Turbo 400 out of a 71 442. Presently I have the body off the frame and am assembling everything that I possibly can before starting the bodywork. Today I went to install the driveshaft that came with the car and it is about 4-1/2" too short... I have read here and other places that the driveshaft that I need should be 54-1/4" from U-joint center to center. There is no way that I am going to get a 54-1/4" driveshaft to fit. When I measure, it looks like I need about 52-1/4". Is there any chance that I have set something up wrong? The frame pads are already overhanging the front of the crossmember by a little bit so I think that the engine is in the correct place. The transmission cross member is located in the last set of holes. Has anybody heard of anything like this? I can get a driveshaft made up, but I want to make sure that I have not done something else wrong before I have something made up that is not right. thanks \Darryl
If the oil pan is not hitting the frame and the transmission crossmember lines up, then the engine and transmission are in the right place. Best bet is to pop the yoke off the drive shaft, stick it into the trans as far as it'll go, pull it out about an inch, measure center of u-joint of center of u-joint to the pinion yoke. I just recently had a driveshaft extended by a driveline shop and it cost me $120 and took about three hours.
I just have the chassis with no weight on it. Will 1" be enough? ---------- Post added at 11:31 PM ---------- Previous post was at 11:13 PM ---------- And does anybody have any idea why it would not be 54-1/4"??
Just curious. Which set of engine holes did you bolt the mounts to? If you used the front 1st and 3rd, it would shove the motor back a few inches. Not sure how the transmission would line up though.
Motor mounts are bolted to 2nd and 4rth holes. ---------- Post added at 10:09 AM ---------- Previous post was at 10:03 AM ---------- The 442 transmission that I have has a 4" tail shaft. The last owner must have had a 9" tail shaft tranny in to use the driveshaft that came with the car. I am just puzzled why the 54-1/4 will be too long.
Wait till you have the car back together and then have a shop measure and build you a drive shaft... No risk this way.
Thats what I will do. I just keep thinking that I am missing something as to why it would be different than the length that everyone else has used with the same powertrain. Thanks
Perhaps your car was in an accident or the rear axle or trans is not in the original position? It might account for a difference in length. I would get it together and have a drive shaft shop tell you what it will need to be. I used Henderson's here in Cleveland and they were great. Dave
like others said wait until it's back together and the suspension is fully loaded. denny's driveshafts has a measuring worksheet that is fool proof and their drive shafts are second to none, all i run in my cars.
