LOL.....Mike, Just drive the thing for a little while. You dont have to always be working on it.

Although I feel lost now since the truck is parked in the carport and not the garage. I'm like WTF do I do now.

You would definitely add some ponies with that head swap. Why not just juice it!.!.!. :evilg:

 

I know how you feel!Lol Hell I feel like I'm done now sense I got it inspected!!Lol I'm going to put some juice to it.Just dont know when Lol.

 

you will lose power if it a striaght stock ls6 head swap like a 243 casting. The chambers are bigger ie you lose compression enuff to make you lose hp.

 

Im not so sure, he should be better off with better flowing heads. The increased flow gain will over compensate for the lower compression.

Its what all 07+ 5.3Ls come with now (#799/#243 heads) and they are rated for more power now too.

 

True, but the newer Gen IV 5.3's also have flat top pistons to bring the compression up. HTH

 

they have diff. cams. On his stock 04 5.3 a unmodified ls6 head will make it lose hp perfect example is ls1 guys taking 5.3 heads to bump there compression.

 

He has a cam and I'm sure he would mill those heads too.

But, I would think the bigger valve and better flow would offset the 10fwhp loss due to the compression.

 

Either way, better heads is always a good idea. (Sig)

 

+1 on the head swap, but don't bolt them on bare. Have them worked over first by the machine shop. Mill the heads no more than .030" and you'll have at least returned the compression back to stock 9.5:1 but mid and top end pulling power will have increased. You may see 15hp across the board from ~3500 to red line with peak gains around ~5400 or so. That's how the typical 5.3L reacts.

 

Thanks for all the input.Whatever I do,I will have the heads milled.

 

all 5.3s have flat tops. 4.8s have dishes. and there all hypernetic pistons.

 

Would the newer 5.3 heads(243/799)be as good as the LS6 heads?

all 5.3's are not flat top.My 04 heads have dished pistons.Like brentg454 said the gen.IV LSx motors are flat top.

 

Would the newer 5.3 heads(243/799)be as good as the LS6 heads?

Yes, they are the exact same heads, no difference.

The actual LS6 #243 heads just have lightweight valves, except for that they are exactly the same.

 

my bad i got it backwards the 4.8s are all flat topped. yea there the same heads.

 

here ya go::::ls1 camaro heads=67cc's--10.19 compression --port volume,200/70 int/exh
ls6 vett heads=65cc's=10.46 compression 210/75 port volume
lq9(6.0) escalade and silveradoSS=71cc's 10.08 compression 210/75 port volume
lq4(6.0) truck and suv(non caddy) 71cc's 9.41 compression 210/75 port volume
lm4(5.3) 61cc's 9.49 compression 200/70 port volume
lr4(4.8)61 cc's 9.47 compression 200/70 port volume
You can always change the head gaskets thickness to come up with whatever compression or close to it as you need.....This is all I can think of right now.....LOL, yea right!!!This is out of one of my mags

 

ok thanks!

 

:eyes:

 

you will lose hp with the head swap if you dont mill them, its been tested. get the heads worked, and milled, or you can put in some 4.8 pistons and not need to mill them.

 

...or you can put in some 4.8 pistons and not need to mill them.

Unless for some reason a user is displacement limited (racing class, aluminum block ect) 4.8L pistons are a bad investment. If you're getting new pistons solely for higher compression, bore the 5.3L block over to 5.7L and use flat top LS1 pistons which are far more common for less cost. In the same vehicle, gas mileage will virtually be unchanged between the two motors but you'll have about 10% more torque, everywhere.

 

5.3 to a 5.7 hope he dosen't want to drive that truck on the street. Thats like boring it 110 over lol. Will wrk on a race motor not street friendly been done several times and proven not road worthy to risky.

 

I want to know what's in this guy's hashish pipe. Must be good stuff.

The 5.3L can take a .118" overbore without a hitch. Don't tell me it doesn't work or it's not street friendly. I've built two iron block LS1's now with great success, both are daily driven. I would not have recommended the overbore if I did not think it was plausible. I don't shoot from the hip when I talk, which you should be mindful of.

 

Its not just a weekend truck at the track.I drive it almost everyday.I'll probably just add some juice to it.Try to keep it hidden,HaHa!!My buddy has an 2002 35th aniv.Camaro ls1 with the ls6 intake,heads.Just trying to keep up with him.Lol!

 

Tell me how a iron block 5.7 can only be a race motor and not street friendly?

 

http://www.ls1tech.com/forums/new-p...ms/new-products-showcase/992760-5-7l-iron-block-forged-piston-1499-99-core.html

 

Hey,why yall jacking my thread?Lol!!I don't care,hell the more I read about these engines,the more I know!

 

well you can do what you want. But i will not overbore a block that much and i live in texas were its very hot and we have had these overbored 5.3 overheat cause of the paper thin sleaves. I speak from firsthand. I wouldn't do it but in the end it to each there own.

 

See,I learned something else!lilsonoma I am as maticulous as you,just in other area's of the truck.If your going to do something do it right and make it look the best you can.Course that comes with trial and error.Just my o2,Mike