Thread: 64 Chevy SWB SBC 700R drive shaft

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I need some help! I have a SBC in my 64 SWB Chevy truck and currently run a turbo 400 trany but want to change to a 700R4. I have the 700R4 ready to go in but the old drive shaft is too long since the R4 is about 2.5" longer than the 400.

Anybody out there know what donor vehicle drive shaft will work so I can install the 700R4 behind the SBC on my SWB 1964 Chevy truck? I can have mine cut and rebalanced but I'm moving soon and hoped to keep it simple.

Please respond to my email address if possible and soon! I appreciate any help!! THANKS

take your drive shaft to the drive shaft shop have it shortened and ballanced,will plud rite on the 700r trans,same splines

sorry i mean have it lenghtened or just get another drive shaft thats 2 long and shorten it.not expenssive either way.350 400 700r all the same yoke to trans splines.

Originally posted by luvtnt
take your drive shaft to the drive shaft shop have it shortened and ballanced,will plud rite on the 700r trans,same splines

I agree. I am doing this same thing with my 69 Camaro.

luvtnt, you were right the first time, shortened.

rednilla, with the 700R4 mounted, push the trans yoke onto the trans output shaft until it bottoms out, then slide it back out 3/4" to 1". Now, measure between the centerline of the trans yoke u-joint and the centerline of the pinion yoke u-joint. That's the length you want to give the shop that shortens your shaft. Try to position the trans yoke in a place other than where the seal has been riding in the past so you don't get a leak with your new installation.

Is it better to cut the driveshaft say 3/4' or cut the yoke?

Originally posted by techinspector1
... measure between the centerline of the trans yoke u-joint and the centerline of the pinion yoke u-joint. That's the length you want to give the shop that shortens your shaft....

Do you have a diagram showing the measuring points?

Originally posted by Sgrinder
Is it better to cut the driveshaft say 3/4' or cut the yoke?

When doing a transmission swap, or a rearend swap for that matter, you must use the proper length driveshaft. The method I was outlining is what I've used for years. Push the front yoke onto the trans output shaft until it bottoms out, then slide it back out 3/4" to 1". The reason for this is to allow some play so that the yoke doesn't bottom out in the trans while driving. The driveshaft is usually installed on a down-angle with the vehicle at rest, so that as the suspension works and the pinion moves up in relation to the trans, the yoke is pushed further into the trans. It is constantly changing the engagement on the output shaft as the suspension works, so you want to leave 3/4-1 inch of play so that the yoke doesn't bottom out. Changing the length of the yoke that slides onto the trans shaft will only change the amount of total spline engagement.