Ran my RhS headed 410 Friday....

this isnt bad at all

in august mine ran 11.05 @ 122 mp/h

the engine consist of

1973 .040 over
scatt serie 9000 cranck 4.0'' stroke
w2 race heads fully ported
1.6 harland sharp rockers
10.27 cr.
m1 intake 1/2 spacer
dynamic 9 inch converter

full trim car even with a complete stereo sisteme
sub woofer and everything

it ran 10.79 at miramichi last falls

with better air and running about the same here where I leave 11.06
so better track condition help alote

also hade the same problem as your the tires was unloading
I fix that with clamps behind the tires about 1 inch

it cure the problem with out shock only 4 pieces of flat barre and 8 bolts

maybe you can try the same