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Looking for how to tune my Caltracs info.

Gunner1

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Had my caltracs up and running for almost a year now with no issue. 63 Polara. 440/10.5 to1/Isky 292 mega cam/CNC stealths/RPM air gap/750 Holley DP/Dougs452 headers and all MSD. 727 RMVB 3000 stall. 275/60/15 tires. Everything worked ok till I replaced the 2.93 open with a 3.73 Detroit setup. Now the engine responds like it’s on nitrous, but the rear end axle hops like it’s on meth. GTX John told me to add some Caltrac shocks and set the pinion angle to about 2. He’s a smart man I’m doing that as I type. I have been searching for axle hop threads online but none seem to come up. It’s going on jackstands this week so I can check for loose or overtightened bolts, pinion angles,preloads all the basics. This is a big deal going on a creeper again. I have missed doing my own wrenching. All the work on my car was done by others. But I’m feeling better and I want to get back out on the strip. I’m worried about breaking something expensive with the axle dance. My limited caltrac knowledge says most likely the rear shocks are topping out and yanking the tire off the road then slamming back down and on and on. Stock very old shocks in front and rear.
Bob
 
You were right about GTX John, he's the wise man in the arena . A minimum of 5- 5 1/2 front end rise is necessary. That and the proper amount of flats from neutral of preload on the bars
Shocks play a large role
 
Someone here recently said a Cal Trac sticky is available on the A bodies site.
Mike
 
Here ya go

 
So I put it up on jack stands and measured everything. From ride height to full shock extension I have 3 3/4 inch’s on the front and 2 3/4 on the rear. Trans was 0 degrees, diff on the u joint flange is 1 degree down. I’m guessing the shocks topped out and were unloading the tires. Tomorrow is more measurements and looking for a harmonic vibration from 2800 to 3500. Check driveshaft phasing. It’s a new shaft. Thanks for all the help.
 
What rear spring are you using? Rear shocks that are too short will unload the rear tires on launch.
 
Caltrac splits in std weight. Sits at about stock height. Using factory 318 torsion bars.
 
I'm no expert but ran Caltrac's for several years my 69 Charger bracket car. You need adjustable shocks on front and rear. My car was setup on the softest settings after several test passes. Can't speak for a street car but my car only ran in the low 7's in the eight and would print 60 ft times.
 
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