Swaping PG for TH400 in 67SS Chevelle. I have read many archives and postings on just how much to shorten the drive shaft. Some say 1" others say 3/4". My calculations put it closer to 3/4". I suppose 1/4" doesn't make that much difference, or does it. Anyone got the straight scoop. Also, which length yoke to buy, Year One offers 2 or 3.

i'd recoment calling up or going to a local machine shot and talking to them about the amount to cut. I'm sure they have done it before. Not sure about the yoke tho, thay can prob help you there too.

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OWNER OF 66 CHEVELLE MALIBU
Check out page dedicated to resto of my chevelle. still being made. (http://www.geocities.com/MotorCity/Shop/9801/)
Team Chevelle # 424
Canadian Classics Chevelles and Beaumonts #393
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I had a driveshaft shortened 3" for my 69 Chevy truck and it cost me $53.00.



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Bob (Pa.)

1963 Impala 283
1966 Chevelle SS 409
1969 Malibu 307
1972 Malibu 307
1969 Chevy stepside 350

Bob's 409 Chevy Page

http://members.spree.com/entertainment/mr409/bob_s_409_chevy_page_index.html

Yeah, before you freak out and do all this research you have to find a good driveline shop in your area. They should know, and they might even make you measure the length which is what I had to do for my custom shaft. They should set you up with the yokes for same/better than YO. If you've got some beef in the engine bay, you might want to upgrade to 1330 or 1350 yokes at this time.

Why not measure the length of the PG, measure the 400 and subtract? Am I overlooking something?
rick

Push the yoke all the way into the tranny then back it out 3/4". Now measure from the center of the U-joint (on the yoke) to the centerline of the where the U-joint goes on the pinion. I used a magnet to hold the tape measure on the yoke & pulled the tape measure towards the tranny. It's easier if you have a friend help you measure it though.
Driveline Northwest told me you should have 3/4" to 1" play. Any tighter and you'll take a chance of breaking a tranny. Happened to me on a TH350 once http://www.chevelles.com/forum/mad.gif And to loose, well....you get the picture http://www.chevelles.com/forum/eek.gif
Follow Genes advice though and ask them to spin it at a higher rpm when they balance it. Shouldn't cost any more, some refer to this as "Performance Balancing" http://www.chevelles.com/forum/biggrin.gif

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Lowered '67 Elcamino
ZZ430 eng / 4L60 trans
"Canyon Carver"

[This message has been edited by Cardiac (edited 01-06-2000).]