 Since these heads are Vortec...  Since these heads are Vortec style, we gained the improved sealing gaskets up top, but needed to be sure to order a Vortec-style Edelbrock AirGap intake, and also needed center-bolt style valve covers. |  A 650-cfm Speed Demon carb...  A 650-cfm Speed Demon carb seemed like plenty for a 305, promising a good balance of low-end performance and top-end power. The full-throttle manifold vacuum peaked at under 1 in-hg. at the top of the dyno pulls, showing that it had plenty of flow capacity on this engine. |  What was our "Power Pack"...  What was our "Power Pack" worth on the 305? How about 372 hp at 6,100 rpm? However you feel about 305s, you've gotta love that. |
Engine Master Dyno Test
305 CID Chevrolet
901 Engine Dyno
STP Correction Factor
Tested at Westech
| |
|---|
| RPM | Stock TQ | Mod TQ | Stock HP | Mod HP |
| 2,600 | 285 | 290 | 141 | 144 |
| 2,800 | 283 | 297 | 151 | 158 |
| 3,000 | 287 | 320 | 164 | 182 |
| 3,200 | 291 | 328 | 177 | 200 |
| 3,400 | 290 | 334 | 188 | 216 |
| 3,600 | 284 | 337 | 195 | 231 |
| 3,800 | 279 | 340 | 202 | 246 |
| 4,000 | 271 | 346 | 206 | 264 |
| 4,200 | 264 | 349 | 211 | 279 |
| 4,400 | 256 | 349 | 214 | 292 |
| 4,500 | 252 | 350 | 216 | 300 |
| 4,600 | 250 | 348 | 219 | 305 |
| 4,800 | 241 | 344 | 220 | 314 |
| 5,000 | 233 | 342 | 221 | 326 |
| 5,200 | 221 | 343 | 219 | 339 |
| 5,400 | - | 337 | - | 347 |
| 5,600 | - | 330 | - | 352 |
| 5,800 | - | 324 | - | 358 |
| 6,000 | - | 322 | - | 368 |
| 6,100 | - | 320 | - | 372 |
| 6,200 | - | 314 | - | 370 |