Custom headers

[Duke of Cruel]

Hi Guys,

Anyone have some knowledge about pipe lenght, diameter and collecter
size for a 500+ hp ls6.
I am about to make some, and probably are going to use 1 3/4" pipes
that are 26" long going in a merge collector 2 1/2"-3"

If this is all wrong please let me know.

Doc

[z28misfit]

i guess it depends on your cubic inches too from what i hear. i was told 383 and larger motors can run the 1 7/8'' primaries. i may be wrong

[Duke of Cruel]

its the 346 that has been balanced and good rings.
plans for 7000 redline

[Hi-Po]

well here is some basic shit if you dont know already.

Uusally want to stick between 32 and 36 inchs length. The inside diameter is important not OD. But also remember its the ID that really matter more over length. If your really tring for all out performace then def. get equal legth headers. Street headers will usually differ from 2 to 4 inches. Also were do you plan this 500HP? Smaller ID increase flow at low speeds and evacuate the cylinder nicely.Tri-Y headers usually increase power in mid range slightly over 4 tube headers. If its just drag car, adding 8 to 10" to the collector can give you some low end torque. Usually arcers say tri-Y headers usally brodens the torque curve while 4into-one headers tend to be more peaky.

Hope that you use all mandrel bends. I dont know how far your knowldge goes but mandrel is the only way to go. keep in mind that exaust gas speed is important too. get a real good medium.

Also concider a H pipe. Testing has shown from what i understand, that a large diameter H-pipe increase torque at or below peak torque while not subtracting top end horse power. You can look at the H-pipe as adding lenghtto the collector.

that is all i guess.

[Duke of Cruel]

Thanks hi-po

i am making it for a stock balanced and gapless ringed block, that i am building in a Porsche 928 gts. i have ordered a huge inch block, but it will not come until september, so i will use the other to finish up on the install.
DoC

[Hi-Po]

gapless huh? you are a brave man. I sure hope(im sure you did) that you had the utmost professional build this for you. That is very hard to do. I usually just heard of it being straight drag. Might be wrong.

[Duke of Cruel]

gapless huh? you are a brave man. I sure hope(im sure you did) that you had the utmost professional build this for you. That is very hard to do. I usually just heard of it being straight drag. Might be wrong.

I put em in there my self. havent tried em before, teh theory just
sounded right, and they where on sale. If they suck, they must come out.
I build ford sb turbo´s and Porsche flat six turbo´s for race cars, but build my first ls ayear ago, mostly for their cubes and 175 kg.
DoC

[Hi-Po]

What all did you get balanced/blueprinted?

Just curious/ nerd

[Duke of Cruel]

Got pullys,crank and flywheel balanced at autosprint. its all in the block, heads on
ready to put in the 928. hoping to test drive it in a month or so.

[Hi-Po]

best a luck!