I have a set of 906 heads on my never tough again workbench that went 9.80’s in my Duster 30 years ago. .030 over, TRW piston, stock crank 440. I’m thinking those ones are up there in air flow but I never put one on my flowbench

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