Can someone help me with a question about my drive shaft? I have a 1970 dart swinger 340 4 speed 8 3/4 rear end. I built this from a roller. I have a drive shaft that is to short. it seems to measure 3 1/4 across. I bought another shaft but it measures 3" across. will this work? what was it from the factory? Thanks Bill.
Drive shaft
- Thread starter slx70
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g413
Well-Known Member
I have attached a useful pdf file that someone else referenced on this site. I hope it comes through.
Added: It looks like the file came through and your car is on the list.
Added: It looks like the file came through and your car is on the list.
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fishy68
Tyr Fryr's Inc.
Are you saying the drive shaft diameter is smaller or the u-joints measure smaller across them?
g413
Well-Known Member
According to the chart, it looks like your original car came with a 3.25" diameter shaft. This is beefier than a 3" shaft and will handle more torque and HP. But Mopar also used a 3.0" on a 340 Duster with an 8.75. IMO, unless you've got a monster HP engine or you use it for drag racing, the 3" driveshaft should be okay.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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Make sure it has the correct yokes on each end.I think the diameter has more to do with the yoke sizes, for OEM SBMs.
There are yokes for 7260 joints, and different yokes for 7290 joints. 7260s will not take 400ftlbs for long, if your car hooks.7290s will take it for a while, and then it's custom time for 1350s. On the street,with 275 or smaller street tires, you can run anything,behind an sbm.. It's not always the driveshaft that goes. My street car kept smashing the needles to bits. One time it it ripped the straps off the rear yoke, and the driveshaft plopped onto the pavement at about 30mph..
I have 1350 ends on my shaft now, a 1350 coming out the GearVendor, and a 7290 on the diff with an adapter-joint. No more troubles.I run 295 street tires. Cooper Cobras.They say those tires are crap, I dunno; they make real good skates.
There are yokes for 7260 joints, and different yokes for 7290 joints. 7260s will not take 400ftlbs for long, if your car hooks.7290s will take it for a while, and then it's custom time for 1350s. On the street,with 275 or smaller street tires, you can run anything,behind an sbm.. It's not always the driveshaft that goes. My street car kept smashing the needles to bits. One time it it ripped the straps off the rear yoke, and the driveshaft plopped onto the pavement at about 30mph..
I have 1350 ends on my shaft now, a 1350 coming out the GearVendor, and a 7290 on the diff with an adapter-joint. No more troubles.I run 295 street tires. Cooper Cobras.They say those tires are crap, I dunno; they make real good skates.
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trapster
Well-Known Member
SO where do you get a new driveshaft?
Dr diff Strange Engineering Driveshaft
or
CUSTOM BUILT (MOPAR) DRIVE SHAFT 7290 & 7260 SERIES FOR DODGE, CHRY & PLYMOUTH
Dr diff Strange Engineering Driveshaft
or
CUSTOM BUILT (MOPAR) DRIVE SHAFT 7290 & 7260 SERIES FOR DODGE, CHRY & PLYMOUTH
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