Blown 5.3, Looking for 6.0, which ones fit?

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Matthew Jeschke

Matthew Jeschke

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I feel a bit crazy to do this... I wonder if I just order a LQ9 off the internet?

It'll cost more but it seems I can get an LQ9 rebuilt minutes the intake for under $3000.

https://carpartplanet.com/remanufactured-2003-cadillac-escalade-engine-56284.html

Otherwise, they are up the road from where I live for around $1000 to $1500 but I have no way to pick the motor up as my truck is blown up :( I'm not sure how to transport a motor from a private party sale 100 miles w/o a truck.
 
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Matthew Jeschke

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Wait I'm crazy. I think I know how to go about this and is SUPER cheap...

1. Buy a Gen III 6000 block.
2. Take parts off my 5.3 that it shares, new or used parts from LQ9 that I need.
3. Reuse the 5.3 Heads as they make more power down low than the heads for the 6.0 (sacrifices a hair up high).

I found the parts (minutes seals, timing chain, machine, etc) and can swing this for well under $1000 to build a LQ9. I also found two different sets of LQ9 heads for under $300 (FB marketplace and ebay).

Only thing, I wonder if I can run a LQ9 tune with the smaller 5.3 heads? I'm about to pull the trigger on this. May call a few junkyards yet but it seems this is the way to go.
 

iamdub

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Wait I'm crazy. I think I know how to go about this and is SUPER cheap...

1. Buy a Gen III 6000 block.
2. Take parts off my 5.3 that it shares, new or used parts from LQ9 that I need.
3. Reuse the 5.3 Heads as they make more power down low than the heads for the 6.0 (sacrifices a hair up high).

I found the parts (minutes seals, timing chain, machine, etc) and can swing this for well under $1000 to build a LQ9. I also found two different sets of LQ9 heads for under $300 (FB marketplace and ebay).

Only thing, I wonder if I can run a LQ9 tune with the smaller 5.3 heads? I'm about to pull the trigger on this. May call a few junkyards yet but it seems this is the way to go.

I can't say how much upper-RPM them heads would cost you. But, they can always be replaced later. If you drive like a grandpa and tow often enough, you may not miss anything.

Or, you can get the 317s and have a stock LQ9. Back when I was shopping for heads for my brother's '05 5.3, we saw 799 (same as 243) everywhere for $250-$350. Settled on a set of low-mile units from a 2010 Silverado for $300. The 243s would make it an iron LS2 and you'd definitely have to run premium.

The LQ9 tune will run with the 5.3 heads plenty well enough to get it to a tuner. I wouldn't romp on it en route to the tuner, though.
 

mattt

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Depends on how in-depth you wanna rebuild it. You could go all out and get the cylinders bored or just honed, which you can hone at home. I'd measure the bores to check for roundness, though. If you happen to get a low-mileage one and the cross-hatching is still strong and even, then machining wouldn't be necessary. You'll need a special tool for the cam bearings. If it were me, I'd spend the couple hundred bucks and let the pros with their special tools and equipment do all the cleaning, measuring and bearing replacing. The heads can just be cleaned and checked for flatness and get new valve seals at a bare minimum. But, it's always nice to have a cleaning pass on them to ensure a flat surface. Since they'll be set up on the machine for the cleaning pass, you may even entertain a light shave to boost compression, depending on your goals. Maybe nix the shave and get thinner head gaskets. Maybe have the shop minimize the lump in the intake runners and blend in the bowls for more CFM. This all depends on what you want out of it as a whole. I'm a fan of high compression (10.5+) on an NA engine, but this demands 89 or 91/93 octane fuel.




This is half true. In the earlier years, pre-'04, the LQ9 was the same as the LQ4 except for the flat top pistons. Around '04/'05, the LQ9 got beefier rods and full-floating wrist pins. If you wanted to, since you're rebuilding it, the money you'd save getting a "boring" ubiquitous (and, therefore cheaper) LQ4 could be put towards aftermarket flat top pistons, making it an LQ9.


Built right, you can make an LQ9 an "iron LS2". The 80lb difference is kinda negligible and the overall cost would be less, depending on how wild you get with it.

The Gen4 "beefier rods" with floating wrist pins didn't only come in LQ9's. The changeover from the earlier connecting rod with pressed wrist pins to the later Gen4 rods happened sometime in 2004. I have an '04 LQ4 that came with the Gen4 rods, so it's not just LQ9 that got the better connecting rods.
 

mattt

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Wait I'm crazy. I think I know how to go about this and is SUPER cheap...

1. Buy a Gen III 6000 block.
2. Take parts off my 5.3 that it shares, new or used parts from LQ9 that I need.
3. Reuse the 5.3 Heads as they make more power down low than the heads for the 6.0 (sacrifices a hair up high).

I found the parts (minutes seals, timing chain, machine, etc) and can swing this for well under $1000 to build a LQ9. I also found two different sets of LQ9 heads for under $300 (FB marketplace and ebay).

Only thing, I wonder if I can run a LQ9 tune with the smaller 5.3 heads? I'm about to pull the trigger on this. May call a few junkyards yet but it seems this is the way to go.

Where are you able to find a Gen III 6.0 block SUPER cheap? Do share.
 

iamdub

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The Gen4 "beefier rods" with floating wrist pins didn't only come in LQ9's. The changeover from the earlier connecting rod with pressed wrist pins to the later Gen4 rods happened sometime in 2004. I have an '04 LQ4 that came with the Gen4 rods, so it's not just LQ9 that got the better connecting rods.

Didn't know that about the LQ4. Good to know!
 

mattt

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Didn't know that about the LQ4. Good to know!


I wonder if the 5.3 's also carried thru with the same change over(mid 2004), but I have not personally opened one of them up so I have no first hand knowledge. 4.8 who knows....because the 4.8 uses a different connecting rod than the 5.3/6.0.
 

mattt

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To the OP, I was in the same boat as you, but my 5.3 didn't go boom. It just has really high mileage and leaks like a stuck squealin' pig. I figured why throw rebuild $$$ at a 5.3, when it's basically the same $$$ to rebuild a 6.0. The hard part is procuring a 6.0 as you've come to find out. Core long blocks in my area run in the $600-$1000 arena and they go quick. At some point you just gotta bite the bullet and drop the coin if you want a 6.0.

One piece of advice; before you agree to purchase any used 6.0, check the cam bearings and cam tunnel in the block prior to purchase. These things are know to eat cam bearings and in the process eat into the block casting of the cam tunnel which makes them nothing more than a boat anchor. Once the cam tunnel is out of round, you will not be able to install new cam bearings into the junk block. It is most common on cam bearing #1 & #5 from what I've been told and seen personally.

I have seen one like this, it's a damn shame that a highly sought after 6.0 LS block is junk after a cam bearing failure that takes out the block.
 

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