its a purchased package from marchperf.com it lines up

The thing is, I have edelbrock 87 complete aluminum heads and a comp cam extreme energy 274 grind already. With the larger valved, aluminum round port style high flow heads and that cam, its gotta be better then these 15s and that cam. the cam seems really wierd according to its specs

why would you put a 389 cam in a 455?

308 112 .405" .447" 83 312 115 .404" .446"
Dur. CL 1.50:1 1.65:1 O.L. Dur. CL 1.50:1 1.65:1

Long duration perhaps to help out with the small valves??, .447/.446 lift at .50 with 1.65 rockers