The Long and ShortFor the budget conscious, the long-block version of the 350 H.O. is an excellent way to get the most out of this package, especially if you already have an intake, carb, and the other accessory pieces. If you are replacing an older small-block, keep in mind that this is a one-piece rear-main-seal engine, so you'll need either a new one-piece flexplate or flywheel. The H.O. engine is fitted with a flat-tappet cam, but the block is configured for a factory hydraulic-roller cam. We'll convert this H.O. engine over to a roller cam later in the buildup series, so if you're thinking of this conversion, it's a great idea. Just hang with us and we'll show it to you.
The Results Are In Test 1: Baseline run of H.O. 350 w/ cast-iron manifolds, 2-inch turbo mufflers and 37 degrees total timing w/91-octane fuelTest 2: Added Hedman 15 1/4-inch headersTest 3: Added Borla 2 1/2-inch stainless steel Pro X/S mufflers and QuickFuel 650-cfm carb
| Test 1 | Test 2 | Test 3 |
| RPM | TQ | HP | TQ | HP | TQ | HP |
| 2,200 | 327 | 137 | 338 | 142 | 339 | 142 |
| 2,400 | 328 | 150 | 343 | 156 | 340 | 155 |
| 2,600 | 334 | 165 | 354 | 175 | 350 | 173 |
| 2,800 | 341 | 182 | 362 | 193 | 365 | 195 |
| 3,000 | 343 | 196 | 363 | 207 | 372 | 212 |
| 3,200 | 350 | 213 | 371 | 226 | 375 | 228 |
| 3,400 | 351 | 227 | 377 | 244 | 380 | 246 |
| 3,600 | 353 | 242 | 380 | 260 | 385 | 264 |
| 3,800 | 354 | 256 | 380 | 275 | 387 | 280 |
| 4,000 | 352 | 268 | 383 | 291 | 388 | 296 |
| 4,200 | 350 | 280 | 382 | 305 | 386 | 309 |
| 4,400 | 348 | 292 | 377 | 316 | 382 | 320 |
| 4,600 | 346 | 303 | 374 | 328 | 378 | 331 |
| 4,800 | 340 | 311 | 364 | 332 | 370 | 338 |
| 5,000 | 331 | 315 | 355 | 338 | 361 | 344 |
| 5,200 | 322 | 319 | 342 | 339 | 351 | 348 |
| 5,400 | 311 | 319 | 331 | 341 | 338 | 348 |
| 5,600 | 301 | 320 | 319 | 340 | 327 | 348 |
| |
| AVG | 337.8 | 249.7 | 360.8 | 267.1 | 365.2 | 270.9 |
| Gains | +23 | +17.4 | +27.4 | +21.2 | |