I have a set of 454 heads, not sure what the description means. Can anyone explain?

Casting #346236
75-87...oval...OPEN...454, 120cc chamber, 225/116cc ports

Those are the peanut port heads with a small intake opening. They are good for a torque engine, but not the greatest for performance builds. Although, some have used them and made strong running engines with them.

1975-1987 oval intake port (more correctly, the small truck peanut port) which have an open chamber with 120cc nominal volume. The intake port is 225cc, the exhaust is 116cc.

See the thread at the top, BBC INFO for some detailed information.

Regards