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downgrading from a 5.3 to a 4.8 2007 Sierra New Body


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Ok this is my issue guys.  

 

I have a 2007 Sierra with 210,000 miles.  Number 6 Cylinder AFM lifter is stuck.  The cost of all lifters and everything has made me decide to just swap the engine.  

 

So I have been pricing a replacement 5.3 engine the LY5 Vin code J for a while now.  About the cheapest I can find is over $1500 and that is usually in the 150,000 miles plus range.  Well I'm scared of those AFM lifters on these just going out again if I buy a junkyard engine.  

 

So I'm thinking of going down to the 4.8.  Mostly because it doesn't have the AFM, and also because the 4.8's are dirt cheap.  I can buy a 4.8 with 150k miles for about $800 bucks.  

 

That is for a LY2 4.8 Vin Code C.  Which would be correct engine for my truck if it had come with a 4.8.  

 

So say I do this, swap my LY5 5.3 to LY2 4.8.   What all would I have to change?   I would mostly probably be using the long block of the 4.8 and attaching all my intake, injectors, etc.  Even though I imagine all that stuff is the exact same anyways between the two.  

 

I am guessing the only thing I need to do is either swap the computer in the engine bay, or get mine reflashed to a stock 4.8 program.  

 

Am I correct in this?  I know this might seem weird to go from a 5.3 to 4.8.  But they are half the price of a 5.3 and I don't do any towing.  My truck is mostly hauling trash and odd stuff and the 4.8 would be than enough power for what I use a truck for.  

 

Am I crazy in thinking of doing this?

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  • 4 weeks later...

The 4.8l in our work trucks are such dogs. Wouldn't ever think of going this way. If you are already thinking of getting the computer flashed, why not go with a non afm 5.3l? Just my 2 cents.

 

Sent from my SM-G900V using Tapatalk

 

 

 

 

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While the 4.8 in the 2001 Sierra work truck I had was fairly reliable, it was a dog as described already.  Do yourself a favor and just go with a 5.3L and fix the thing before you put it in. 

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  • 1 year later...

There is defeinitly a performance reduction in the 4.8L but it is a fairly solid engine.  However- I would suggest getting another 5.3L and while it is out of the truck, doing some mods and a good solid rebuild and AFM delete and such to it.  Much easier and cheaper to do with it out of the engine.  You'll be happy you did.  I had a 2WD company truck- 2001 1500 Sierra Work Truck (SL?)  regular cab standard bed with the 4.8L and it did well.  Blew up the rear end but it did well otherwise.  I really liked it.  yeah it wasn't as quick compared to my at the time 99 Silverado 1500 Z71 4WD 5.3L but if you don't do any mountain driving and do a lot of flat land driving.. the 4.8 wouldn't be bad.

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