Stage 2 Bottom End - Header options

[eop002]

I have a stroked Stage 2 bottom end running GN1R heads, BG intake, 70mm tb. Currently have ATR's 1 1/2" primary SS headers and curious if there are any other options and benefits in running a larger primary header for the GN1 style heads for my combo ? Assuming these headers are readily available.

I have seen the larger primary (1 7/8") Stage 2 headers, but have not seen anything larger than 1 1/2 for the GN1 style heads.

Welcome the inputs.

 

[forcefed3.8's]

You can have custom headers made, but unless you are going deep in the 8's, I don't think it will increase anything but lag.

 

[Nick Micale]

Not an opinion, but actual results show headers we have built for stock type heads with 1-5/8" primary tubes, WILL definitely help with increased HP. :smile:

Using a 70 MM HPQ on my T-Type with a 274 cu. in. alum block, spooling is at least the same, maybe better.

We do custom headers for many applications including CTSV/LS, Mercedes, BMW and others, and all have dyno proven HP increases over stock and aftermarket ones.

Here is the set presently on my car, which is very close to your same build:

 

[eop002]

Nick, I would be interested in seeing the level of power improvement based on your dyno results if you would like to share. it will help set my expectationon what the header change would bring.
Many thanks.

 

[GNDriven]

Subscribed!!

 

[GNDriven]

I understood that ATR made headers with larger primarys than their normal production ones.

 

[John Wilde]

Joe Lubrant / Dan Strezo have or had a set of 1 5/8 primanary headers on their car.

 

[S2V6RACER]

We ran 168+ and I know would have run over 170+ with 1-1/2 primary headers. I'm not sure how fast you want to go but my opinion is unless you are going to go faster than 8.50's then save your money if you have 1-1/2" primaries.

 

[turbobuick]

We ran 168+ and I know would have run over 170+ with 1-1/2 primary headers. I'm not sure how fast you want to go but my opinion is unless you are going to go faster than 8.50's then save your money if you have 1-1/2" primaries.

x2 Modified ATR's 1.5" primaries took me to 8.20's@168. I spent large $$ on custom 1 5/8 headers that made little if any difference IMO.

 

[eop002]

Mid 8's is well beyond my goal. Engine is my daily driver. It sounds like the 1 1/2 are sufficient for where I want to go with the car. Appreciate everyone inputs on the topic.