Depends how tall of tires you have on the rear and how level you want your car to set 500LB springs IMO are overkill I have 28" tall tires on the rear with stock ride height espo leaf spings and fliped the front perch to lower rear another 1" I wanted my 69 valiant to set level ended up using stock spindles + a longer upper shock mount from Denny 10" coil overs with 375# springs with a low deck big block so that's why I'm interested in your final set up
