I'd go as big as you can fit. All the "loss of lowend" stuff is bullshit, in my experience.

 

dang id like to see that. stew had enough problems with the stepped headers...

 

LOL that's what nitrous is for

I figured someone else would say it, figured I'd beat them to the punch

 

jason26 ran the full 2" kooks f-body headers with good fit... https://www.performancetrucks.net/fo...eaders-443336/

I am running the stepped headers and have a slight clearance issue with #6 primary tube. Here are a few threads with some good info.
https://www.performancetrucks.net/fo...eaders-471855/
https://www.performancetrucks.net/fo...verado-503164/
https://www.performancetrucks.net/fo...trucks-490555/

 

I picked up a set of 1 7/8" and i swear i picked up tq, according to the butt dyno, if the builder says 2", do it and like stated above n20 fixes all softness lol

 

lol i know better than that. I put a fast 90 and stepped headers on my LS1 which everyone on tech preaches as a bottom end killers and i gained massive power down low. too bad it never translated to the track. slap them in and find out

 

I'm the builder and I say 2" lol...

 

I agree with this... I had 1 7/8" on a bolt on only LQ9 with plans for more down the road and lost nothing down low. I could MAYBE feel it when the converter was locked at 40 MPH... meaning 1200 RPM, but thats part throttle tip in... not a big concern if its real power and acceleration you are after.