Figured this would interest most. Just got my April Chevy HiPerformance in the mail. They have comparisons of all types of headers with hard numbers.....

1 1/2 Intermediate Flowtech
1 5/8 Long Tube Hooker
1 3/4 Long Tube Hooker
1 7/8 Long Tube Hooker

Didnt see it online yet on their site but then again the magazine just came out so it may be a couple of weeks.

 

So which size is better

 

What about it?
Care to elaborate a bit more?
-Goose

 

Give us the infooooo

 

yeah lets hear it...Do you have the webiste?

 

Maybe he works for them, and therefore is leading us on so we'll all go out and buy it.

<<<<<going out to buy it at lunch...

 

I'm in class now but heading back to work. I'll type up the comparison numbers for the 1 5/8 vs 1 3/4. However, there are charts comparing all to one another.

 

1 3/4 Longtube Hooker vs. 1 5/8 Hooker

Article says the real gains from the 1 3/4 would have been seen had the test been a naturally aspirated 7000 rpm engine

RPM TQ Diff HP Diff
3000 422 +7 241 +4
3100 423 +7 249 +4
3200 422 +5 257 +3
3300 422 +6 265 +3
3400 423 +6 274 +4
3500 425 +5 283 +3
3600 425 -2 295 +3
3700 437 +1 308 +1
3800 444 +1 321 +1
3900 448 -2 333 -1
4000 453 -3 345 -2
4100 458 -3 357 -3
4200 462 -4 369 -4
4300 465 -3 381 -2
4400 466 -2 390 -2
4500 467 +1 400 -0
4600 467 +1 409 -1
4700 464 +0 416 -1
4800 462 -1 422 -1
4900 459 +2 428 +2
5000 455 +3 433 +2
5100 450 +2 437 +2
5200 446 +3 441 +3
5300 441 +5 445 +5
5400 434 +5 446 +5
5500 427 +6 447 +6
5600 421 +7 449 +8
5700 411 +5 446 +6
5800 403 +6 445 +7
5900 393 +4 442 +5
6000 385 +5 440 +4

 

I am a little lost here are they saying the 1 5/8 shorties out preformed the LT?
What car was this done on,a 350 LT1 F-body?
Or a cammed and head small block Chevy or what?
Please list any details you have.

Thanks,
Claude

 

Any more details on this?

thx,
Claude

 

Sorry for the delay. Article said it was a 383 crate motor. I think it was rated over 400 horse out of the box. The diff listed is what the 1 5/8 did compared to the 1 3/4.

 

I read it, and felt that it was very inconclusive.

 

They did a test on the HT 383 a while back with the 230/236 XE cam and airgap performer RPM and a demon 750. They started with regular 1 3/4 uncoated headers and moved to stepped 1 5/8s coated (torque step hedmans) and the difference was very minimal , they said the 1 5/8s out performed the bigger tubes. It was very biased.

 

It was biased because the smaller headers outperformed the larger primaries? Explain.

-Chris

 

I read the article too. It had a bunch of rambling in it, but never really said much. The 1 3/4 did make the most though. I'll get the articles up line in a min