New to the board... Getting ready to do some things to the Avalanche... Very familiar w LSX motors as i own a Z06,Firehawk...

Firstly, looking to add some Headers to my 4wd (Z71) Avalanche. Which ones have the best fit w/o modifying? Will have tuned, DOD turned off, etc.. Shift points tweaked..

My 08 Avlanche has the 243's...? It is the 5.3 motor... I have owned it a couple of years... Just noticed the 243's... Did the 5.3 motor come from the factory with these? Or did the previous owner upgrade?

Purchased truck from Chevy Stealership w 28K on the clock.... Thanks for your input.

 

Every Gen IV 4.8 and 5.3 built has either 243 or 799 casting heads..... and flat top pistons. The 5.3 is 9.9:1 and the 4.8 is a dismal 8.8:1, lol.

 

wooo... hooo 9.9:1.... Thanks for the clarification sir..