1999 K2500 Suburban 7.4L

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Papablunt

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I bought this Suburban from my Dad a couple years back (Nov '19), and I'm finally getting around to showing it some love.

My pops lives in NC and I'm in CO, so we met 'half-way' in Omaha, NE to exchange. It was a wild ride heading back home between the heavy winds and sloppy rag joint, but it pulled just fine.

He pulled his XJ behind so he could get back home:
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And I pulled our Accord back home:
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The tires that were on the 'Burb were pretty horrible. The well worn MTs were incredibly loud, and you could feel each lug under 20mph.
While the OEM wheels are cool, I immediately dropped those in favor of some PYOs. I am a big fan of Wildpeak AT3W tires... these are 265/75-16s:
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Shortly after, I installed 2" Stahl steel spacers at the rear:
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Papablunt

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I bought it with ~176,000 miles, and it had seen better days. It felt sluggish overall, it died on me once, and it just didn't put that grin on my face that I was expecting. Hell, my 5.3L Sierra had more grunt.

So I started tearing into it. It needed a lot of maintenance, which I quickly realized it meant having to pull half the engine apart to get to most of it, so I figured why not throw in some performance upgrades... you know, "while I'm there."

I added:
- Comp XR264 Cam
- Comp Rotator Eliminators
- Comp Beehive Springs
- Comp Tool Steel Retainers
- Crane -0.050" Valve Locks
- Comp Ultrapro Magnum Rockers
- Manley One-Piece Push Rods
- New OEM Lifters (Originally used Comp, but one failed)
- Summit Aluminum Distributor
- LS1 Injectors
- New timing set, lots of sensors, ignition coil, FPR, etc, etc, etc.


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Originally I used Comp lifters, but we had a failed lifter right out of the box. I had read a few things about the quality of their lifters, and after I experienced it myself, I decided against them entirely. I went with new OEM lifters instead.
The valve covers looked horrible. I was going to look at new shiny chrome covers, but decided against it. I went with the unfortunately named "Cummins Beige" color for the valve covers.
 
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Papablunt

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I tried two different sets of valve locks due to the clearance between the rocker roller tip and the valve locks. The 'standard' locks ended up way too close to the roller tip, so I swapped them for Crane valve locks that were 0.050" lower.

Here are the 'standard' height locks. There was no contact using this method, but it was just too close for comfort:
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Crane locks, which brings the locks 0.050" lower, just out of reach of the roller tip:
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Papablunt

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Looks like a good day to put it back together!
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The LS1 injectors dropped right in:
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The Summit Aluminum distributor came with a blue cap that looked a little inferior. I also wasn't a fan of the rotor inside, so I swapped the cap and rotor with OEM. I later found out that the OEM rotor isn't known for longevity, and there's a such thing as a "Blue Streak" rotor that you may want to look into. The aluminum body and distributor gear are why I picked this over other models - the price was a contributor too, being much cheaper than some others I saw.
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Papablunt

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Got the valvetrain adjusted and she sounds purdy! The Comp pushrods that came with the cam kit were 0.250" too long. I ended up going with one-piece Manley pushrods. Probably overkill on my engine to use one-piece PRs. They're a bit heavier, but I doubt it will affect anything.

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Next thing left to do is get a datalog so I can send it over to Blackbear. My whole goal was to get this thing put together and a datalog sent over just in time before Christmas. Weeeee.
 

BNielsen

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As a fellow 454 owner, seeing you tear down and build up your rat makes me want to get mine to the machine shop! Can't wait to see more!
Have you thought about doing the 0411 swap? I did the swap to my 96 and after working out some of the bugs it's been one of my favorite mods to date.

Whereabouts in NC did your dad live?
 

yevgenievich

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Looks nice. I been thinking about Morel vs oem lifters for my build due to higher spring pressure.
 

OutlawDrifter

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Fellow big block long roof owner here, they make great vehicles!

Nice progress so far.
 

Papablunt

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As a fellow 454 owner, seeing you tear down and build up your rat makes me want to get mine to the machine shop! Can't wait to see more!
Have you thought about doing the 0411 swap? I did the swap to my 96 and after working out some of the bugs it's been one of my favorite mods to date.

Whereabouts in NC did your dad live?
I may end up doing the 0411 swap at some point, but I'm thinking since Blackbear can tune my ECM as is, I may just leave it. I am sure I would gain some additional refinement and (maybe) power from an 0411 swap. Certainly something on my list, and will definitely need to happen if I pull the trigger on a procharger. My Dad lives in Rockingham, NC. A small town in between Charolotte and Fayetteville.


Looks nice. I been thinking about Morel vs oem lifters for my build due to higher spring pressure.
I've heard great things about Morel. A buddy of mine has a very similar setup on his 8.1, he basically copied my setup haha: New OEM lifters, beehives, same lift cam, same 1.7 ratio rockers. Been towing heavy for a couple years now. I dug around a bit, and it appears OEM lifters are good for ~325# spring pressure. The beehives are hitting 370#, but that is at maximum compression (they're variable rate springs, NOT linear). Who knows what my spring pressure is at max lift, but the slow-mo video I posted shows that I've still got a little bit to go before coil bind. I'm hoping / guessing the max spring pressure is at or below 325#, but you know what they say about assumptions! Time will tell how these OEM lifters hold up.


Fellow big block long roof owner here, they make great vehicles!

Nice progress so far.
Looking forward to seeing many years out of this one! It is going to replace my 99 Sierra 5.3 for camping and other adventures.
 

BNielsen

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I may end up doing the 0411 swap at some point, but I'm thinking since Blackbear can tune my ECM as is, I may just leave it. I am sure I would gain some additional refinement and (maybe) power from an 0411 swap. Certainly something on my list, and will definitely need to happen if I pull the trigger on a procharger. My Dad lives in Rockingham, NC. A small town in between Charolotte and Fayetteville.



I've heard great things about Morel. A buddy of mine has a very similar setup on his 8.1, he basically copied my setup haha: New OEM lifters, beehives, same lift cam, same 1.7 ratio rockers. Been towing heavy for a couple years now. I dug around a bit, and it appears OEM lifters are good for ~325# spring pressure. The beehives are hitting 370#, but that is at maximum compression (they're variable rate springs, NOT linear). Who knows what my spring pressure is at max lift, but the slow-mo video I posted shows that I've still got a little bit to go before coil bind. I'm hoping / guessing the max spring pressure is at or below 325#, but you know what they say about assumptions! Time will tell how these OEM lifters hold up.



Looking forward to seeing many years out of this one! It is going to replace my 99 Sierra 5.3 for camping and other adventures.

I've been to Rockingham quite a few times! I live in a small city between Albemarle and Salisbury; small world!
 
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