Kooks 2 inch Headers

[Ransom]

Thinking about picking up a set, but wanted to see if anyone had any issues with installing them or clearance.

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[andrewtac]

In for the info currently 1 7/8 and did pretty much everything else.

 

[Ransom]

Surely, someone has installed these.

 

[LOL WUT]

Surely, someone has installed these.

Most go with 1 7/8 headers. Especially if naturally aspirated. Really no point in going 2” NA. However, kooks products notoriously fit great.

 

[Cory S]

Unless you’re going to drag race only and make 1200+whp, 1 7/8” is more ideal.

 

[2021 Mach 1]

I'm NA and have 1.75 Kooks, very happy with 'em.

 

[AZlb5.0]

What are your future plans with the car? Staying NA or doing some type of power adder?

 

[K4fxd]

Unless you’re going to drag race only and make 1200+whp, 1 7/8” is more ideal.

I've seen back to back dyno runs that show no loss of torque between the 1-7/8 and 2 inch on a stock coyote. HP was slightly higher due to shifting up in the RPM range.

 

[Ransom]

I understand how header primary/secondary, diameter/length can effect hp/tq.
The car may stay NA but may go boost down the road, havent made up my mind yet.

I would rather move peak torque up higher in the rpm band.

 

[bankyf]

I went from Kooks 1 3/4" to 1 7/8" and the difference in bolt access was pretty significant. I can only imagine that access on the 2" would be a nightmare.

 

[GregO]

I understand how header primary/secondary, diameter/length can effect hp/tq.
The car may stay NA but may go boost down the road, havent made up my mind yet.

I would rather move peak torque up higher in the rpm band.

That’s mostly 2 valve header dynamics.
4 valve not so much.

 

[LethalPerformance]

We ran the 1-7/8" Kooks headers on our 2018 GT project Goldmember. No issues with installation at all. We've sold a ton of the 2" ones to our customers over the years and not once have I heard of any issues with fitment from our customer who installed them.

My personal take on it is that 1-7/8" is great for NA as well as boosted setups. Goldmember was powered by a Gen5 3.0L Whipple and was making around the 1100rwhp range. I went 8.64@157 in that car. I don't believe at that level that we would have seen any significant increase in performance with the 2" ones. With that said the only time I really recommend the 2" headers is if you're going for an all out race setup and are looking for every bit of power possible. Otherwise the 1-7/8" work great even for mid to low 8 sec combos.



Let us know if there's anything else we can help you with.

Thanks!

 

[Ransom]

That’s mostly 2 valve header dynamics.
4 valve not so much.

In what way does primary diameter/length effect dohc vs ohv?

What are your thoughts on megaphone/reverse cone setups?

We ran the 1-7/8" Kooks headers on our 2018 GT project Goldmember. No issues with installation at all. We've sold a ton of the 2" ones to our customers over the years and not once have I heard of any issues with fitment from our customer who installed them.

My personal take on it is that 1-7/8" is great for NA as well as boosted setups. Goldmember was powered by a Gen5 3.0L Whipple and was making around the 1100rwhp range. I went 8.64@157 in that car. I don't believe at that level that we would have seen any significant increase in performance with the 2" ones. With that said the only time I really recommend the 2" headers is if you're going for an all out race setup and are looking for every bit of power possible. Otherwise the 1-7/8" work great even for mid to low 8 sec combos.



Let us know if there's anything else we can help you with.

Thanks!

It will be more so an all out race setup, as its not my daily. If i can gain even the smallest amount hp/tq over the other and basically spend the same amount of money, ill take it. Really my only concern is fitment, i have read that with LTH brand the AC has to be removed.

I will definitely be in touch once i make up my mind.

 

[GregO]

In what way does primary diameter/length effect dohc vs ohv?

2V heads require a more refined header whereas 4V can afford to be a sloppy design and still make great power.

What are your thoughts on megaphone/reverse cone setups?

With open collector race headers I think there is merit to the collector “choke” that Calvin Elston uses on his headers but again the collector choke is more effective on 2V heads than 4V.

https://burnsstainless.com/blogs/articles-1/merge-collectors

You might want to spend some time on Don Terrell’s Speed Talk and search Calvin Elston. Calvin is a Wizard.

https://www.speed-talk.com/forum/index.php

If you want 2.00" primary 4:1 headers go for it. This isn't old school 2V non-VVT flow dynamics.

 

[illtal]

It will be more so an all out race setup, as its not my daily. If i can gain even the smallest amount hp/tq over the other and basically spend the same amount of money, ill take it. Really my only concern is fitment, i have read that with LTH brand the AC has to be removed.

I will definitely be in touch once i make up my mind.

If it is all out race lose the AC. I believe the 2 in primaries might impact the AC lines, and they will be closer to the frame. You don't want them touching anything and causing a false knock.

That being said some brands 1-7/8 have these same problems.

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