A properly built 408 will shred those tires at the track. As suggested, try a little less air or get a pair of real drag slicks mounted on a 2nd set of rims just for racing. Go with a tall slick (like a 28") to get a larger contact patch during launch.
I guess I am in the minority here, but I'd try the leafs first as they are and then later try removing one of the leafs. As Dave Zimerman (Team Z) told me, a softer suspension might help the caltracs to work as designed. He even had me running the Rancho's at 2-3 on both sides.
Originally I ran 5 leafs and they worked OK with a similar suspension as you have, but with the 6 cyl springs installed. Times with my stick car were 1.7ish. I removed a leaf and although the car was more springy on the street, I made several 1.6x passes that same week and even a 1.600 even. I ran a few more weeks like that and then put the leaf back in. My times increased again (although the heat of summer may have had something to do with that.) I've since moved to the Caltrac monoleafs and really never seen the same times as I had with the 5 leafs converted to 4--but I also have 50 more hp to contend with this year. I might have to swap to the much more expensive double adjustable rear shocks.
As for what you have, set the Caltracs on the upper hole, and give them 1/4 turn of preload on both sides with someone sitting in the driver's seat. That will plant the rear tires the hardest during launch if you get good front end rise. Try shocks at 3 and if you get spring wrap, move up to 6. Set the CE's to their lightest setting, which is suppose to be 90/10. Get someone to film your launch for you from different sides and from the rear. It is amazing what you can uncover after reviewing a launch video, especially in slow motion.
In the end, since each car is different, be prepared to try different things. There is no "one" formula that works on each and every car.