[Mr70]

Welcome
Double check your TH400 suffix,as they were unique to the L-78's.
Is your cars CON VIN# stamped into the drivers side horizontal pan rail?
Although the one your showing now with a March 26th assembly date is possible for your cars timeline,the CF suffix was used in LS-3 402/330HP & L-34 402/350HP engines...get the serial # off the al.tag too..
CW was the highshift point TH400 for your car.
Is your #854 block a 4 bolt main also?
Are your Ex.Manifolds tapped for A.I.R?
Curious what your SS wheel assembly dates are,as they were an extra option on the Nova and not automatically included with the Super Sport packg.