Headers, how much power can be lost?

[260DET]

LS3 into a Z31 auto race car project, I'm a simple man but realise that a can of worms is the popular design model for 'race' headers. But I like the look and practicality of the good block hugger designs, particularly where there is not much difference between the pipe lengths, the collectors look like they perform a useful function just like with the more complicated ones. So what's the go, have we some proper power comparisons here, will just a few horses be lost or will it be significant? Stock engine except for a yet to be decided upon medium cam.

[JMortensen]

This looks like a question for ls1tech.com. From some quick reading, shorties are worth next to nothing compared to stock manifolds, big increases possible with long tubes.

[JoeK]

Yeah, I'm far from the expert on the subject but from the googling I did it seemed like the big difference between the 2 was gains in low end torque with long tubes. And it is all about the torque isn't it, especially when racing 

Edited May 5, 2018 by JoeK

[260DET]

Decided to play it safe, particularly as space is largely an unknown at present , so I've decided on a set of used HSV headers. They can always be replaced without losing much if power is not satisfactory. No luck on LS1 Tech, pic of HSV's.. 

[G-Tech]

i looked at using those headers cause they use them on newer z/28's so they must make power. i decided not to cause the primary tubes can be real small at different points(like 1-1/2in). i went with these billy boat c5 shorty headers (1-5/8 primaries). im supposed to be around 440whp but ended up at 405whp. my tuner said if i had 1 3/4in or even 1-7/8 primaries and long tubes that i could do alot better. i just dont have the room in my s130. basically with my ls6 intake and dart heads, im getting air in, just not getting it out. every winter i think i need to do something about it, then spring comes and i take it for a rip and realize its got plenty of power..i think you will be happy with those, they have to flow really good if they run them on z/28's

[260DET]

Be interesting to know why the HSV/Z28 headers went with a more complex 1-3 2-4 plumbing arrangement, it would be more expensive to make than the usual 1-2 3-4.

[RebekahsZ]

Block huggers make it easier to work on the car. There was a comparison somebody did on here a few years ago comparing block huggers against the group-buy stainless long tubes:  I recall the difference was 17hp. For me, with 400hp, 17 wasn’t worth the fight.  There’s a pretty good comparison on an Engine Masters YouTube program out there. 

[alainburon]

On ‎5‎/‎5‎/‎2018 at 2:48 PM, JoeK said:

Yeah, I'm far from the expert on the subject but from the googling I did it seemed like the big difference between the 2 was gains in low end torque with long tubes. And it is all about the torque isn't it, especially when racing 

You hit the nail right on the head. The main gains from long tubes is low end torque and it changes your power band completely having more usable power throughout. If chasing numbers is the goal then long tubes are not worth the money but if getting the most performance out of your LS motor is the goal then there is no other way to go.

[260DET]

For my purposes only performance above 3500 is relevant. As it is now, more acceleration above 5000 is required so a cam change is next. At this time no other modifications are contemplated because all the indications are that the right cam/header combination should do the job.