409 cylinder heads ?

[Verne_Frantz]

Casey,
There were two different style heads on "single four barrel" 409s in '63. You didn't make the distinction of which engine you need heads for.
The 340hp versions (hydraulic lifters, 10.5 CR) uses casting number 3830817. These heads aren't that expensive. This engine uses a Rochester 4-jet carb.
The 400hp versions (solid lifters, 11.0 CR) use casting number 3814690 heads. These have large ports and only fit with the aluminum single four or dual four manifolds. The 400hp uses a Carter AFB. Unfortunately, today the prices for the 690 heads are obscene. Expect to pay $1200 or more for a decent set.

Good luck
Verne.