Headers on motor with fast burn d port heads,and motor in car with headers and exhaust pipe coming from headers.all clear with no real issues, went into a single 3 inch pipe with no conerter back to flowmaster muffler.

Which model are those ?

CC12 or CC15, I am guessing.

CC3dp for angle spark plugs

So how does she run with Sanderson headers vs the OEM cast iron manifolds?

Car has not had manifolds on it for over 5 yrs. has had headers on old 305 now it has a new gm crate motor