Cam sizing

Hey guys im looking at putting a new cam in my 318 thats in my duster. I have found one that im interested in http://www.summitracing.com/parts/CCA-CL20-671-4/ its a .484 lift cam or http://www.summitracing.com/parts/CCA-CL20-672-4/ .508 cam i have a set of stock 318 and a set of 360 J heads. My main questions are would i have to change valve springs or do anything else to the heads or anything? Also ill be running a 650 double pumper with a 360 intake while i try to find a cheap used aluminum single plane intake. Any and all help is greatly appreciated im trying to make some more power out of it to run at monster mopar!!