While at Edelbrock, we had project engineer Ulysses Gonzales hoist the cylinder heads onto their SuperFlow 1020 flow bench. Edelbrock was right on target with the published specs, and Ulysses had every reason to be enthusiastic about the results. With over 260 cfm of intake flow at hand, there's enough flow here to make solidly over 500 hp out of the box. The exhaust numbers are also quite good.
Flow Data
Edelbrock Magnum (PN 61771)
| Lift | In (cfm) | Exh (cfm) |
| .100" | 62 | 52 |
| .200" | 119 | 105 |
| .300" | 175 | 142 |
| .400" | 225 | 169 |
| .500" | 251 | 185 |
| .600" | 260 | 190 |
Tested on Edelbrock's SuperFlow 1020 Flowbench
Test depression 28-inches H2O