'69 RT 440-4spd: 90% cruise/street & 10% 1/4 mile track- change to SS springs..?

[Pacey]

or keep the Mopar Performance HD springs on there? The shocks are shot as well. What are the highest quality shocks (front and back) I can install on here? Should I switch to Super Stock Springs in the rear or keep the Mopar Performance HD springs out back? I want to be able to hook well.

[Mike DC]

 
The factory (R/T) leaf springs are already stiffer than ideal for ride/handling.  I wouldn't go any stiffer than that on a 90% street car. 


Shocks . . . Bilsteins or Konis are good stuff.  Avoid KYBs.     


Stiffening up the unibody is also a good idea.  Nobody ever does that and regrets it.  US Car Tools makes good pieces for the job.

   

[metallicareload99]

I went from XP leaf springs (318 car) to the XHD springs to now CalTrac split mono springs. Each change was to stiffer springs, but I was fine with that. "Springs really only need to be stiff enough to not bottom out," is something someone smarter than me once wrote

I used stock replacement junk and Bilstein shocks on the XHD springs. I should be embarrassed to admit this, but I never noticed much difference between the Bilsteins vs Napa $20. For a street car I would choose the XHD over the Super Stock springs and good shocks

And absolutely get some frame stiffening welded in if you aren't overly concerned with a stock look. Torque boxes and subframe connectors is one of the best things done on my car!