I wish I understood more on what you are trying to do but I run a .660 lift roller cam on my Edelbrock heads. I open them for a 1.550 spring and shim as needed. Easy peasy.

1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27

Livin and lovin life one day at a time