5.7 vs 5.3

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Tempted

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My 95 was a turd towing.(granted it was not a vortec) after swapping in The 6.0 I could not be happier in any way. I loaded a 00 extended cab dodge half ton on our 20' car hauler and towed 75 mph down the highway in overdrive! With no downshifting. It's worlds difference

I've had the opposite results. My 99 5.3 Z71(150k) with 3.42s is a turd compared to my 94 Sierra(300k) 2wd reg/short 5.7 with 3.42s.
 

scarybowtie

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There has to be something wrong man, this wasn't my first tbi 350 truck or my first ls powered truck. The vortec 5.7s are fine (owned one of those as well), but the tbi trucks are just too far behind. A 5.3 even on the pitiful stock tune should have no problem handling a tbi truck.
 

scarybowtie

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how do the 6.0s work in our trucks, like whats involved in putting one in, i know of course tuning and all that, but do you have to get a pcm from the truck it came from or is there a way to make it work with the existing one, i would loooove to put a 6.0 in my truck, my stepdads trailblazer ss with the ls2 6.0 hauled ass, it was unbelievable how a vehicle that heavy could go so fast, that and a built 4l80e and you could have a serious tow rig and a serious sleeper from a stop light haha

http://www.ls1truck.com/forums/showthread.php?t=9535&goto=newpost
 

ChrisAU

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I feel like I'm driving a school bus towing a yacht full of fat people when I get in my 5.7L TBI ECSB after driving my 5.3L Tahoe. And I thought my '92 I had in high school was a fast V-8 truck LOL.
 

97c1500

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My tuned 5.3 in my new truck would walk all over my old tuned 5.7 vortec es the 350 did have more low end grunt but once you get it above 3k it falls on its face compared to the 5.3
 

Tempted

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My tuned 5.3 in my new truck would walk all over my old tuned 5.7 vortec es the 350 did have more low end grunt but once you get it above 3k it falls on its face compared to the 5.3

Yeah my 5.3 has decent power on the big end, but is a dog from a dig with a load. My 5.7 certainly out pulls my 5.3 from a dead stop. Again, my 5.3 is in an extended cab Z71 so it is having to push a little more weight than my 2wd reg/short. I pull heavy, heavy loads on a routine basis and the 94 has been leaps and bounds a better tow rig. I've gone through 3 4L60Es but I have never cracked the motor. Valve covers have never been removed. The 99 Z71 is on its second motor and 2nd trans, and has half as many miles. It also hasn't towed near as much as the 5.7. I'm gonna keep the old TBI 5.7 in it until it pops. I know I can get 500k out of it but it would be cool to have a million mile half ton that has always been a tow truck. When it gives up a Cummins is going back in. Should make for a near perfect tow rig with a Cummins/Allison/14 bolt.
 

scarybowtie

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Most of the lack of low end you notice in the 5.3s is torque management and the factory tune. A good tune from nelson, blackbear or equivalent will do wonders for your low end
 

Tempted

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Yeah I have SCT Advantage software, just haven't felt like making a custom tune for it. If anyone has the tables of a good tune I sure would like to see them ;)
 

jantzer

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A 5.3 with any mods at all will walk all over a TBI 5.7 with stock heads on it.
 

jantzer

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The TBI 5.7 with some good aftermarket heads/cam makes good power however. Had a some trickflow heads on one that ran really well.
 
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