Rear spring question

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Mopower71

Mopower71

Speed Demon
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Besides changing the pinon angle. What effect would moving the front spring eye down about 1 1/2" or so?
I have the offset spring hangers on the car, and they prohibit me from using the upper hole on my caltrac.
Two options, drill new holes lower in the front spring hanger, or cut the lower edge off the hanger. If I just cut them off, the caltrac front pivot can only move 1/2" to maybe 3/4" forward. If I drill new holes down farther it would have a longer travel clearance.
So, effects of moving hole lower?
 
I had a pair of Super Stock spring mounts in my 70 Charger for years. I used them because they allowed me to drill holes HIGHER on the bracket to lower the car without de-arching the springs. I later had a Gear Vendors overdrive unit in the car. I had a series of vibrations with the GV in the car that always annoyed me. It was a rebuilt first generation unit with a bolted on yoke at the output. I had to use a 4wd style slip and spline driveshaft. I ended up pulling the GV out and went back to a regular 727 setup. At that same time, I put stock spring hangers back in. All the vibrations went away. Trouble is, I can't clearly say where the cause of the vibration was. I'm not sure what the difference in pinion angle is with a 1 3/4" difference in hole position. I do know now that a higher hole position is going the WRONG way for guys building a drag car since the smart move is a static downward pinion angle to counteract the axle rotation at WOT.
 
Kern Dog said:
I had a pair of Super Stock spring mounts in my 70 Charger for years. I used them because they allowed me to drill holes HIGHER on the bracket to lower the car without de-arching the springs. I later had a Gear Vendors overdrive unit in the car. I had a series of vibrations with the GV in the car that always annoyed me. It was a rebuilt first generation unit with a bolted on yoke at the output. I had to use a 4wd style slip and spline driveshaft. I ended up pulling the GV out and went back to a regular 727 setup. At that same time, I put stock spring hangers back in. All the vibrations went away. Trouble is, I can't clearly say where the cause of the vibration was. I'm not sure what the difference in pinion angle is with a 1 3/4" difference in hole position. I do know now that a higher hole position is going the WRONG way for guys building a drag car since the smart move is a static downward pinion angle to counteract the axle rotation at WOT.
Click to expand...
did the gearvenders set up require a really short drive shaft ?
 
The Charger has a 117" wheelbase so even with the GV in there the drive shaft wasn't too short. Yeah, it shortens it by about a footto 14" I can't recall exactly. I saved my stock drive shaft and just reused it when I pulled the GV out. The shaft I used with the GV was a fixed yoke on each end with a slip/spline toward the front, like in the front of a 4wd.
That is why I an unsure of where the vibration started: The angle and drive shaft were changed at the same time so it is difficult to pinpoint but I'd lean toward the drive shaft.
 
Of course, I jacked it up and pulled the wheels and looked it over. I didnt remember that the offset spring hanger and the the frame interfere with each other. Frame was dented in to clear the front leaf spring bolt.
Not sure how close it will be after moving the spring down on the front hanger.
 
This is how close it is

20170411_154437.jpg
 
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