Can I replace a 6.0 with a 5.3 with no modifications?

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Sep 23, 2010 | 11:38 AM

indiansprings

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Can I replace a 6.0 with a 5.3 with no modifications?

New to the site. I just bought a 2003 K3500 truck with a trashed 6.0, sounds like a bent rod. I have an oppurtunity to buy a very low mileage 5.3 very cheap. I don't pull big loads so the hp/torque issue is not a big deal.
Will I have to change computers or any of the wiring harness. I assume it will bolt right up to the 480le tranny. Any comments/help would be appreciated.

Sep 23, 2010 | 11:51 AM

miller456

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you should be able to just do a direct drop with no real changes, i dropped a 6.0 in my car and didnt need to change anything. The pcm will still be used, im not sure if your getting a complete longblock? but u may have to look at the pig tails on the injectors matching up or using the ones from ur current 6.0. Also use the flexplate from your current 6.0 so you dont have any starter issues with the 5.3.

Sep 23, 2010 | 12:04 PM

indiansprings

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Thank you for the reply. The 5.3 is a complete engine with all the accessories. I'm going to start pulling the LQ4 this evening. Being new to the LS engines, it will be a learning curve compared to the old pre 80 small blocks we're used to working with. Glad I found this site.

Again thanks for the help.

Sep 23, 2010 | 12:12 PM

Damian

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I would not put a 5.3L in a 3500. Too much weight. That thing will be a gutless turd with no power and horrible gas mileage.

Sep 23, 2010 | 12:17 PM

blsnelling

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Buy the right engine for the truck. A LQ4 can be had for reasonable money. All you need is a long block.

Sep 23, 2010 | 03:03 PM

miller456

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just for reference i bought a shortblock 6.0 from a guy on here name burgers i think for $450 shipped with 72k miles and got heads later from him for $75 shipped. He gets 6.0s all the time and sells them here, I would try pming him and see what he has.

Sep 23, 2010 | 04:08 PM

claytonisbob

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Quote:

Originally Posted by miller456

That's what I would do, just find a short block and swap all your parts onto it and you won't have to worry about the tune or anything. I wouldn't say the 5.3 would be gutless, but it would probably be noticeably slower than you'd think.