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Old Mar 31, 2012 | 01:11 PM
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Default 5.3 mods

Im looking to get a 5.3 truck in the near future. I know people are putting ls6 cams in them. I was wondering what yall thought about 5.3 with ls6 cam, ls1 heads, and ls1 or ls6 intake.
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Old Mar 31, 2012 | 01:39 PM
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LS6 cam and LS6 valve springs work pretty good in a 5.3 truck, but the Comp Cams 212/218 cam is better. I would not do LS1 heads, they will lower the compression ratio too much and flow is not any better. The LS1 intake sucks and the LS6 intake will have interference problems unless it's modded.
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Old Apr 1, 2012 | 09:32 PM
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what kind of interference issues?
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Old Apr 2, 2012 | 04:19 PM
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Default 5.3 gto cam

Hi, highjacking this thread with similar question about this set up. I have a 5.3 with 862 heads and a gto cam. also have 1.75 rockers. will this set up work for a 3000# street car?
what valve springs stock or gto?
thanks for your time.
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Old Apr 2, 2012 | 05:13 PM
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Originally Posted by batboy
LS6 cam and LS6 valve springs work pretty good in a 5.3 truck, but the Comp Cams 212/218 cam is better. I would not do LS1 heads, they will lower the compression ratio too much and flow is not any better. The LS1 intake sucks and the LS6 intake will have interference problems unless it's modded.
Agree. Use the LS6 springs or recommended Comp spring with the 212/218. Add a 2.00" intake valve to the stock 5.3 heads and have them ported by someone who knows what their doing. You already have a good head with the 5.3s. If you're on a budget, the truck intake outflows the LS1. If you can afford the LS6, that's your next upgrade. Skip the LS1 intake. Improve your exhaust and get a tune. You'll have a real strong runner.
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Old Apr 2, 2012 | 05:50 PM
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The accessory brackets and alternator is what interfers (I think). Notice how the truck intake is really tall? I know the LS6 manifold can be swapped, but you have to mod some stuff. The truck intake manifold is pretty good anyway, you'll not gain much.

Originally Posted by ronjax
Hi, highjacking this thread with similar question about this set up. I have a 5.3 with 862 heads and a gto cam. also have 1.75 rockers. will this set up work for a 3000# street car?
what valve springs stock or gto?
thanks for your time.
Which GTO cam and springs? 2004 LS1 or 2005-2006 LS2? Don't use the LS1 springs. Some of the LS2 springs are the same as the LS6 springs and some are wimpy. Since you have higher ratio rockers, I'd invest in new springs, at least LS6 ones.
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Old Apr 3, 2012 | 06:36 PM
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ok got the lowdown apparently the cam & springs are from a 04 gto.
so back to square 1 the heads are on the motor with no springs but
have shims in seats. he had a big cam that was set up by a gm specialist
in the 5.3 before he bought the gto motor and swaped over the cam &
springs
. I got the left overs .
do I need to remove the shims or leave them there before instaling new springs?
Also are ls3 cams good for this set up?
how about ls3 cams good or useless? are yellow gm springs any good?
thanks again

Last edited by ronjax; Apr 3, 2012 at 06:37 PM. Reason: adding more
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Old Apr 4, 2012 | 11:54 PM
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Do you have to modify the ls6 intake to fit the 5.3 like you do to fit the ls1?
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Old Apr 5, 2012 | 12:03 AM
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no the manifold itself isnt what needs to be modded the idler pulley needs to be moved or removed the water pump neck interferes with the throttle linkage theres a couple different ways to address that issue either by "massaging" the neck to clear , running an f- body pump with 3/4 inch spacers or the newer ls3 vette pump with i believe inch n a quarter spacers and the coolant crossover tube either needs to be modified or replaced with the ls6 crossover n block off's
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Old Apr 5, 2012 | 01:06 PM
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So is it even worth all that trouble to put t it on. How much hp gain would I get?
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Old Apr 6, 2012 | 08:37 AM
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Ive been reading up on mods for the 5.3l in my 04 Avalanche, and from what I gather I would be better off having my stock intake ported rather than swap to an LS6 intake. I just saw a thread the other day a company was advertising porting and polishing for truck intakes and TBs for $325 if you send them yours with a 3 day turn around. I would have to do some looking to find the thread again but if I find it Ill post a link
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Old Apr 7, 2012 | 10:33 AM
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hi again is the ls3 cam any good for a stock 5.3?
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Old Apr 7, 2012 | 11:28 AM
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Do you mean a stock LS3 cam? Better do some research, I was thinking they had only a single bolt instead of the gen III three bolts for the timing gear. LS3 cams generally have a bigger duration split pattern than you probably want.
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Old Apr 9, 2012 | 06:17 PM
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hi, looking for advice on a factory cam or lower priced cam for a hot rod with a stock 5.3 not a racer but have cam out & thought it would make a nice upgrade. thanks
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Old Apr 11, 2012 | 12:46 AM
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Either an LS6 cam 2001 has .525" lift or 2002-2004 has .551" lift or an LS2 cam is the same as the 2001 LS6 cam . You can find 1 in the classifieds here 4 about $50-60 but You'll need the newer timing cover that has the cam sensor in the timing cover (Rupperts used auto in Ok for $35 plus shipping) and the LS2 chain and gears and lengthen the cam sensor wires and switch the 2 outside wires . Brand new GM yellow springs at Fred Beans Parts 4 $59
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Old Apr 20, 2012 | 11:05 AM
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Originally Posted by chrisfrost
Either an LS6 cam 2001 has .525" lift or 2002-2004 has .551" lift or an LS2 cam is the same as the 2001 LS6 cam . You can find 1 in the classifieds here 4 about $50-60 but You'll need the newer timing cover that has the cam sensor in the timing cover (Rupperts used auto in Ok for $35 plus shipping) and the LS2 chain and gears and lengthen the cam sensor wires and switch the 2 outside wires . Brand new GM yellow springs at Fred Beans Parts 4 $59
I believe if I remember correctly to run the LS6 cam you will need to run LS6 values also. They a different length ,probably need the whole value train package.
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Old Apr 20, 2012 | 12:05 PM
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Value?

Just need to use the correct length pushrod.
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Old Oct 11, 2013 | 06:34 PM
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I have a question I bought an LSA cam off a cts-v and want to install it in my 5.3l what mods will I have to make I know I need a single bolt cover meaning I'm gonna need to change timing gear chain also will a ls3 timing gear fit the same eat as the one from my 5.3
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Old Sep 4, 2014 | 07:14 PM
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After reading a few threads and this one, I've come to the conclusion that I might have messed up.
02' Chevy 1500 5.3 motor. Has 317 heads, ls9 headgaskets, mild port on exhaust to match the 5.3 manifolds. Otherwise stock. I bought a 2013 camaro ss ls3 cam, springs, chain, cam gear. I was reading some 3 bolt cam I have in the car now, and the ls3 is a single bolt. I'm not a genius, but that don't sound good to me.

Option 1 sell cam, springs ect ect.....buy the right cam.
Option 2, buy lower cover plate, do some **** with cam sensor...... ect ect.(No ****** clue)
Option 3, remove motor from chevelle and drop in 496 BBC, cause these ls motors and so many options are sounding like Honda's and all there Bullshit.
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Old Sep 4, 2014 | 07:21 PM
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I have a 2001 5.3 lm7 with 208-218 .550 lift ls6 cam, ls6 intake manifold, stock heads milled .030, with ls6 sprigs and correct pushrods. Longtubes and a tune made 320 hp on a chassis dyno in my firebird. About to put a 150 shot on it.
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