I am gonna install a stock bottom end LS1 with Ls6 heads, cam and intake off a 2002 Z06 with headers and ory.

Do I NEED 28lb injectors on this setup?

 

short term, no

 

No more mods are planned for this car, its a trackday HPDE car. 400hp is plenty, If I want to go faster on track I will take out weight.


So, yes or no?

 

i would say yes. As those vehicles that you are taking those parts off came with 28# injectors.

Those 26# injectors are going to be screaming at the top of their lungs....

 

pushing your luck with a track only car, stock injectors are cheap

 

My stock 26lb injectors were at 93% duty cycle at WOT@6200 rpm on a bolt on LS1 making 355 rwhp. After installing a cam it went to 108%, so they quickly came out in favor of GM ASA injectors (~42lb). My duty cycle now peaks around 70% at 6500rpm. All of these values were with an AFR of roughly 12.7:1. The safe max is 80%, so I think you'll be well over that level, and being a road race/HPDE car you definitely need that extra safety margin so your motor doesnt

 

grab you some 30# or 36# and you will be set.