Real talk: exhaust manifolds on 360 Dart

273 said
Here's a manifold/header shootout on a 300+hp 360 the difference was 1-5hp depending what rpm.

https://www.motortrend.com/how-to/mopp-0307-installing-exhaust-headers-into-300hp-crate-engine/

Horsepower
RPM 318 360 340 SHT 1 58 tti 1 34
2500 186 185 187 189 187 189 187
3000 223 223 225 226 228 228 226
3500 269 271 272 276 280 281 279
4000 299 301 306 307 314 318 312
4500 311 313 315 321 319 326 321
4600 311 314 315 320 317 327 319
5000 303 304 308 315 312 316 311
5400 281 291 289 295 282 296 289

Yeah, I remember that. Jim Laroy also did a comparison between Stock and HP manifolds and saw zero, zero, ZERO difference. So yeah.

Horsepower
RPM	318	360	340	SHT	1 58	tti	1 34
2500	186	185	187	189	187	189	187
3000	223	223	225	226	228	228	226
3500	269	271	272	276	280	281	279
4000	299	301	306	307	314	318	312
4500	311	313	315	321	319	326	321
4600	311	314	315	320	317	327	319
5000	303	304	308	315	312	316	311
5400	281	291	289	295	282	296	289