IMO, with an elephant sitting on the nose of your car, 500# sounds light for a car that you actually want to drive without worry on the street. If this is predominately a street/strip car, than yes, they may seem a bit heavy, although they will improve your consistentcy.

.94 t-bars with a hemi @ 155# rate would be, IMO, too light. To duplicate that in a coil over may be 250-300# spring, again depending on motion ratio of the lower control arm.

But it is your car and you know your driving preferences better than us.