20RWHP, 20RWTQ from just the headers. With tune, I say 50 RWHP, 50 RWTQ combined headers/tune gain.

 

L76 or LS3?

If LS3 thats some good lulz! G8 with a screaming LS3 haha.

Vids or it didnt happen.

 

L76 motor

 

if he's putting it on a dyno jet I'm gonna say 340ish whp. Seems to be the norm for a longtube/intake/tuned g8. Next up he should just do the dod delete and cam, be right in the 400-430whp area depending on what cam he goes with.