edzsilverss

iTrader: (4)

Has anyone ever slapped some stock ls1 heads on a 5.3 motor? I have a friend who's uncle has a SSR truck and it was the last year before they put the ls1 in them. I have my old set of 853 heads from my 99 camaro laying around and he was wondering if they would give the 5.3 a little more power. I don't even know if they will bolt on or not but he is wanting to try it. He is also wanting to try a ls6 intake at the same time. Will the heads and ls6 intake bolt on to a 5.3 motor?

TooLateVTEC

iTrader: (2)

Dont think he would want to do that b/c the bore on a 5.3 is 3.78 and on an LS1 its 3.9X so it will kill the compression.

IZRED

The 5.3's have better heads, don't they? I just looked at my GMC Sierra and it has 243 heads.

TooLateVTEC

iTrader: (2)

What year is your sierra?

As far as I know, it should NOT have 243 heads on it from the factory.

WSsick

iTrader: (13)

this would be the problem i see you running into. i wouldnt mind finding a for sure answer on this, as my friend said we could swap heads for $200, from his 05 silverado 5.3.

L33_944

05 silverado... if its 4WD, will have LS6 heads

NemeSS

iTrader: (127)

it will not have ls6 heads, it will have ls2 heads.
ls2 and ls6 use same casting buy not same designation
ls6 use sodium filled liteweight valves(expensive)
some of the trucks are equipped with 243 and 799 heads which are the same as ls2 but come with flat top pistons.

NemeSS

iTrader: (127)

if the ssr is alredy equipped with either 243 or 799 heads, then the ls1 heads are a downgrade.
usually the 5.3 use to use dish pistons. but the new ones using 243 and 799 all use flat tops with no relieves

IZRED

It's a 2008 GMC Sierra, 1500 Crew Cab, 4 speed auto. with 3:73's.