rear springs

i have been doing a lot of reading here the last few days...and from what i have read best thing to do is go a get you a weight on the car....weight the car with the driver in it then push the front off the scale then weight the back with the driver ...then you can fig. out what springs you need... i use to race my duster was a 340 in it and car would do ok but now that i have been in to learning what need to be done i see things diff... and car would/could have went faster...i have 02/03 ss springs and went a best of 1.67 60' and a buddy has stock springs 73 duster and been 1.58 60'.... do some reading or ask ???????? to learn... i now know some of the problem i had with my car.... mike:wack:

i spent a lot of money in places i didnt need to spent if the car would have worked /hooked right ...just saying