Here's a stock low cr 2bbl 318 in dyno trim with headers labeled Base pretty flat from 2000-3500 rpm but so does the Modified (Mod 1-2) xe262h with 4bbl and spacer mod 2.
TORQUE SUPERFLOW 901 DYNO-TESTED AT WESTECH | |||
RPM | BASE | MOD 1 | MOD 2 |
2,000 | 292 | ||
2,500 | 287 | ||
3,000 | 287 | 338 | 336 |
3,500 | 272 | 335 | 340 |
4,000 | 248 | 326 | 330 |
4500 | 218 | 309 | 319 |
5,000 | 188 | 285 | 296 |
5,500 | 250 | 258 |