Exhaust headers, LS series engines

[HSVREDSLED]

Originally Posted by Rebel1

How can I justify my claims about the performance factor of these standard manifolds?. Go the Australian LS1 site....do a search. You'll find plenty of comment and tests that imply that the standard manifolds are great up to the point of installing a cam.
Cheers Les

.....................Un-tuned.........Tuned
Pacemaker.......hp lbs/ft..........hp..lbs/ft

1.5" Tri-Y.........339 349.......... 364 373
1.625" Tri-Y......353 357.......... 370 379
1.5" 4>1 ..........309 341.......... 364 379
1.375"..............339 354.......... 360 374
1.625" 4>1........349 355.......... 368 378
1.75" 4>1.........340 344.......... 371 381


Sams Brand XX

1-5/8 t-y&2.5"....352 358........ 376 383
1-5/8 4>1..........344 354........ 374 380

Genie

1-5/8 4>1..........347 353....... 368 377
1-5/8 Tri-Y........345 355........ 374 382

HM Headers

1-5/8 & 2.5........349 355......... 370 379
1-5/8 & 2.25......343 352........ 372 381

Hurricane

1-½ T-Y...........346 356......... 363 375
1-5/8 T-Y.........350 358......... 369 380

DiFilippo
4>1..................343 356........ 374 381

HSV
4>1..................340 349........ 365 373

CAPA
4>1 .................356 356........ 371 377

Wildcat
1-5/8...............346 353........ 370 376

Advance
1-5/8 T-Y.........355 358........ 373 382

Hi-Tech
1-5/8...............352 357........ 372 380

Std Manifold
.....................347 349........ 367 372

**This has been faithfully & accurately pasted, with no fudging of ANY figures!

(Copied from LS1 website.)