Just cause things help over 5000 rpm don't mean they can't also help under 5000 rpm.
I'm not recommending you to build anything like this engine but look at the power it makes between 2500 to 5000 rpm at 2700 it's already making as much or more than stock 318 by 3900 it's making more than you want by 5000 rpm it's making over 400 hp a 1000 rpms sooner than those 400 hp 318 builds, they didn't do it by strangling the engine. Obviously not saying always go big but doesn't mean you got strangle your engine either.
On The Dyno DTS Dyno Data Performance Crankshaft 323CI Small-Block Mopar
| RPM | TQ | HP |
| 2,500 | 337 | 161 |
| 2,600 | 350 | 173 |
| 2,700 | 357 | 183 |
| 2,800 | 357 | 190 |
| 2,900 | 356 | 196 |
| 3,000 | 351 | 201 |
| 3,100 | 345 | 204 |
| 3,200 | 339 | 207 |
| 3,300 | 343 | 216 |
| 3,400 | 356 | 230 |
| 3,500 | 371 | 247 |
| 3,600 | 385 | 264 |
| 3,700 | 396 | 279 |
| 3,800 | 404 | 292 |
| 3,900 | 410 | 305 |
| 4,000 | 415 | 316 |
| 4,100 | 418 | 327 |
| 4,200 | 420 | 336 |
| 4,300 | 422 | 345 |
| 4,400 | 421 | 353 |
| 4,500 | 420 | 360 |
| 4,600 | 421 | 369 |
| 4,700 | 425 | 380 |
| 4,800 | 426 | 390 |
| 4,900 | 427 | 398 |
| 5,000 | 427 | 407 |
| 5,100 | 427 | 414 |
| 5,200 | 426 | 421 |
| 5,300 | 425 | 428 |
| 5,400 | 423 | 435 |
| 5,500 | 421 | 440 |
| 5,600 | 419 | 446 |
| 5,700 | 417 | 453 |
| 5,800 | 415 | 458 |
| 5,900 | 412 | 462 |
| 6,000 | 407 | 465 |
| 6,100 | 401 | 466 |
| 6,200 | 397 | 469 |
| 6,300 | 393 | 471 |
| 6,400 | 390 | 475 |
| 6,500 | 386 | 477 |