5.3 Or 6.0l Heads

[OUTLAW525YUP]

I have a 2002 aluminum headed 5.3 out of a truck and an all iron 6.0l out of an 2003 truck, both have pistion slap and will need to be bored out (got the 5.3 with all the fixens for $200 core charge) I want to use the 6.0 blockand bore it out and put larger pistions in it. Question is, will the alluminum 5.3 heads be better than the iron 6.0 heads. I want to lower the weight of the engine package.

[BudRacing]

Weightwise-yes. Powerwise-doubtful.
I'd sell both sets of heads and buy a nice set of LS2 style heads.

[91sonomast]

what he said
buy some L76's

[AmericanMuscle]

you can get decent flowing ls1 or ls6 heads for cheap, you could also see about getting the 5.3's ported, and any of those options would kick up your compression.

[OUTLAW525YUP]

Okay so no real power difference just weight. Where do you guys suggest I put these heads on and where would I get a new set of heads for cheap from?

[AmericanMuscle]

new is not cheap.

rebuilt or in good contition check out e-bay and ls1teck.com classifieds. also check your local craigslist, classifieds, and local salvage yards.

[AceHaag]

if your 6.0 is all iron it is a 2000 after 2001 they all had aluminum heads

[01cherryreds10]

Search around for the late 90's Silverado's to which I beleive had Vortec heads, that when you port them they are as good as any aftermarket heads.

[OUTLAW525YUP]

I have been looking around and it seems alot of people are usiing the 5.3 heads and getting them ported to stage 2.5. Can any one elaborate.
BlackX can you recommend a good porter in the edmonton, red deer area?

[91sonomast]

yes i did a little searching and you are right, some people are getting these ported. but if u were to go the L76 route, those heads new from GMpartsdirect or GM performance parts, im pretty they have valves, springs, and retainers all installed are like 400ish a piece, which isnt bad, all u need is rocker arms.

[Bone_s10]

the 5.3 and 4.8 heads are good for higher compresion but you can mill any head down to preform the same job

my vote is get a head job done on the 5.3 heads or upgrade to ls1 or aftermarket heads

[BudRacing]

Quote: Originally Posted by 01cherryreds10

Search around for the late 90's Silverado's to which I beleive had Vortec heads, that when you port them they are as good as any aftermarket heads.

Uhhh... what?

[OUTLAW525YUP]

Yeah but that means buying a new intake and such, thats why I bought the 5.3

[01cherryreds10]

Quote: Originally Posted by BudRacing

Uhhh... what?

No idea don't listen to me I have a V6

[LS2Sonoma]

dont waste your money on the 5.3 heads, theyre not worth it. the best and cheapest power gain is going to be with LS6 heads; casting 243. you can pick up a set for around $600. if you want more power than that, look into a set of aftermarket heads

the L76 route is great too and are dirt cheap, but youll be changing your intake, throttle body, and wiring as well

[horsepwraddict]

5.3 heads flow about the same as a stock ls1 head, but with a smaller chamber. Lots of f-body guys have swapped over to 5.3 heads to up their compression. If you already have the 5.3 heads i say use them and get them touched up. If you wanna go new, buy some l92's brand new and have a killer set of heads....and they are dirt cheap for what they are.

[BudRacing]

But the L92s aren't known for their power down low. I think the 243s would be better for the street.

[lilsonoma]

Quote: Originally Posted by AceHaag

if your 6.0 is all iron it is a 2000 after 2001 they all had aluminum heads

True. So now the question is, is his motor truly a 2003 or are the heads actually aluminum and not iron?

What are the casting numbers on the heads?

[spikely23]

5.3 heads on the 6oh would be some pretty extreme compression, i think the chambers are only like 59cc's compared to 69cc's on the new 6oh's the newer 6oh heads (317s) flow the same as the ls6 heads are cheap and can be milled to get decent compression for the street. You could also use the ls6 heads which flow great, would bolt on and give you a nice compression ratio. I think the l92 heads are great but they require alot of work and extra money: a five hundred dollar intake, and finding the right camshaft for them is tough for example. budget and goals make a big different as to which would be the best route

[lilsonoma]

61.15cc's for the 5.3L heads and 71cc's for the 6.0L heads if my memory serves me. 5.3L heads untouched would raise the compression at least 1.5 which is assuming stock head gasket and all. 10.5-11 is a tad high for cheap motor.

The 243's are a tried and true head swap. All you'll need are slightly dished pistons to avoid running a really thick head gasket. I'd stick with 10:1 compression for 89 low grade octane and under 10.5:1 for middle grade 90-91 octane. Any higher will require premium or a retard on the timing. A good tune will help the most to avoid detonation. Then again there is the simple option to find a set of junkyard 317 6.0L heads, mill them down a few CC, and have a shop port match and polish them. For about the same cost as eBay/classified 243's that go for about $400-600, you could have more reasonable compression ratios, better throttle response, higher RPM range and matched components throughout the build (intake manifold to heads, heads to exhaust manifolds/headers).

[OUTLAW525YUP]

The 6.0 may not be out of an 03 it's been sitting here at the dealer for a while but yes the heads are fore sure iron, and since the cylinder need to be bored I think I will just go with the 5.3 heads, get some pistions so that I can lower compression enough to run 87 octane. There is no way in hell that I am going to run 89 or higher cuz I plan to drive this thing alot and I dont want to go buy and plat a money tree in the back to pay for the fuel.

[philntx]

Quote: Originally Posted by 01cherryreds10

Search around for the late 90's Silverado's to which I beleive had Vortec heads, that when you port them they are as good as any aftermarket heads.

This head won't fit on the newer Gen 3 engine. Get educated!

[lilsonoma]

Quote: Originally Posted by OUTLAW525YUP

The 6.0 may not be out of an 03 it's been sitting here at the dealer for a while but yes the heads are fore sure iron, and since the cylinder need to be bored I think I will just go with the 5.3 heads, get some pistions so that I can lower compression enough to run 87 octane. There is no way in hell that I am going to run 89 or higher cuz I plan to drive this thing alot and I dont want to go buy and plat a money tree in the back to pay for the fuel.

The only pistons you'll find with that much dish are going to be over $500 dollars at least without rings. OEM replacement pistons for the 370 are all under $300 with rings with the same specs on the pistons, find the LQ9 pistons so they're flat top. If you're not planning on winding this motor to 7000 rpms or spraying 150hp shots of nitrous or more, stock will be fine. Junkyard aluminum 6.0L heads are all over the place, check Car-part.com. $150-200 bucks and you have your heads. You'd be running stock compression ratios for the LQ9 which is 10:1...perfect for low grade gas.