chevy_silverado07

Hey guys so I'm having alot of doubts....I bought some ls6/799 heads off a 5.3 08 silverado I wanna know Is the HP gain good? Also how bad is the gas mileage drop? And last question is there a difference in sound as far as being louder?...help is very much appreciated

dmelvin

iTrader: (8)

The heads will need to be shaved .030 in order to keep your current compression ratio. You'll more than likely see a little bit more fuel mileage. You cam will really enjoy the extra airflow.

Won't be a bad idea to think about a retune as well.

LS1TRUCKGUY

iTrader: (7)

no difference in sound... as said above, youll need to mill them to keep your currnet compression ratio the same

chevy_silverado07

The guy I got em from did a good job with milling them and clean em up real good and definetly doing a retune what do yal think as far as HP gain?....I might go from 3.23 gears to 3.73 as well just dont no yet

La Blue 05

iTrader: (1)

maybe 20-30 hp gain

chevy_silverado07

Thats what I'm betting on....I got a friend installing em for about 200 so will see soon lop thanks for the help guys....any word on if its a good idea to switch gear ratio to 3.73

06tx4.8

iTrader: (18)

3.73 will wake it up bro, or step up one and do a 3.90. . those heads will help that cam breath some more!

the demonik

i would say 25-35 hp gains with milled heads bro as far as i know

chevy_silverado07

the thing stopping me from switching to 3.73 is I've heard that switching gears makes the truck shake at 100+ so I've heard??

Nflddog1000

Only if the gears are not installed right (backlash)