906 or 915 ?

Here is a recipe for 467hp@5,600 RPM

906 heads (blueprinted, 2.14 / 1.81, Stage 1 port)
10.5:1 comp dome pistons for 88cc chamber
Performer RPM intake
825 holley
284/.528/112 soilid
1.6 ratio rockers (yields .556 lift)
2.125 full length headers