Ran my RhS headed 410 Friday....

I should add that in addition to the correct valving, the shocks need to be long enough to not "top out" and unload the tires. SS springs like to stretch quite a bit. When you put something else on, support the car on jackstands underneath the frame rails and let the rear hang down. With the shock on the top stud, pull it down and see it if it's long enough to reach the bottom stud. If not...they won't work when the SS springs work.

The description of your first run sounds EXACTLY like that's what happened. Did it do the same on the second run? The 60' and ET did pick up quite a bit...

That video of Ken's car is the only way I can see the car run lately. Front End is apart for a freshen...Wilwoods are here but between the 2 of us, we've only had time to work on it about a day and a half. But when we do get out...we ought to save some "AIR"!!