I have had 4 sets of 440source heads on my flowbench and they max out a 267cfm@.700 lift. If you want a nicer set of heads that are reasonable and both at Jegs or Summit with a coupon check out ProMax heads. A friend of mine bought a set of their small block heads and the quality was so much nicer than 440source or Edelbrock heads.

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