I'm rebuilding a 5.3 to resurrect my recently deceased '03 lifted Suburban (35's/4.56's). It does everything from bumper to bumper city traffic deep south full blast AC commuter duty, to playing around at the hunting camp. I'm looking to get as many years as I can out of this truck. With the following performance mods already done:
Efans/big 3/HO alternator
Catback
Tune

An L59 has been yanked from an '03 Yukon. I've also torn it apart, only things still attached to the shortblock are the timing set & cam, everything else is removed. I need help choosing the right parts to put it back together with.

I have questions. Lots and lots of questions.

I want to put a little cam in it. I like the looks of the summit stage 1 high lift cam 8719R1. 261/270 adv dur, 209/217 @ .050 .550"/.550" valve lift & 112 LSA. I'm not stuck on it, but there are reasons I like it. Not too big, not too small. More lift than the other stage 1 cams. Seems like what I'd call in old school SBC lingo a "torque cam". I'm open to other suggestions, but also like the price tag of $300 on the summit cam. I'm rebuilding/beefing up the transmission too so this is a "one foul swoop" attempt at significantly extending the lift of my big white suburban. So I don't object to a little more converter, specifically the 4.2L I6 Trailblazer converter. I don't want or need a choppy idle and don't want or need a 3600 yank converter or whatever. The goal is a very durable warmed up 5.3. I've never done an LS before so learning as I go, will be thankful for any help from you guys. I have the mechanical aptitude and the drive, just not the experience. I pulled the engine and transmission myself with my two hands from a wrecked truck I had to cut up first. And from there got this thing down to the shortblock with all parts removed separated and ID'd in basically less than 3 working days.

I'd like to order some parts and start putting this thing back together soon/ASAP.

Valve guide seals - which ones? Felpro? GM? BTR? Doesn't matter?
I'll change the springs if I need to (BTR "LS6" springs good for .560" lift on amazon for 89.99 look suitable)
Not sure if I need new retainers and locks or not.
Not sure if I need lifters/pushrods or not, also not sure how to tell if I do or don't. (Melling? GM? Delphi?) (7.400",7.3xx"?)
Not sure what gasket set to buy or if I should more piece one together to make sure I get certain MLS head gaskets (certain thickness?), certain crank seals, etc.
Not sure what oil pump/pickup I need. Stock? Melling? Melling HV?
Not sure what timing set I need.
Same with head bolts.
Etc.

Yeah so more or less everything. I'm looking at rockauto, at summitracing, at amazon, and could really use some help, even if it's some other content read and learn. Thanks in advance.

 

Welcome to the forum.

That seems like a good cam over the stock one. You have 3.73 gears, right? What tire size?

You don't really need any aftermarket parts for your rebuild to be honest. Stock heads (but you can get a machine shop to refurbish with new seals), head gaskets, and pushrods. Stock oil pump too.

Are you going to tear into the bottom end? I would recommend you replace the cam bearings.

 

Say the truck is a little hotter than stock tire and a 4.10 gearset. It's on 35's with 4.56 gears. I'm checking valve sealing by pouring water in the chambers, did one yesterday checked out OK...will check the other this weekend, hoping it's tight too. I will replace the valve guide seals myself. Heads are basically disassembled. I am leaving the bottom end alone, hoping that the mirror-like finish on the bores and very very clean appearance behind the front and rear covers is evidence/proof that the entire thing is in pretty good shape.

There's a supposed benefit to running an HV oil pump on a higher mile engine. I'll do it if it really helps, but if it's proven here that's a fairy tale, I'm fine with a stock pump. But GM pump on rockauto is $100, and the Melling M295 stock pump is $70. That's 30 bucks I do or don't need to spend. Part of the point of this thread is me hoping someone can tell me which parts are good or bad or a waste of $ or necessary or whatever. I'm attempting a do it right, do it once buildup here. And the goal is to button it up and not have it leak, tap, knock, etc. AT ALL for a very long time afterwards.

So with a 120k mile set of lifters, that seems old enough that one or more might want to start tapping while cold. I'm not against changing them. Maybe with roller lifters the manufacturer doesn't matter as much as flat tappet lifters with regard to premature failure from subpar materials or manufacturing, but I have a feeling it does. Also have a feeling the differing price points I see (Melling/Mahle @ 11/12 bucks apiece vs GM @ 30 bucks apiece) dictate quality. But I also know GM is quite $$$ proud of their parts too,and sometimes the aftermarkets are the exact same parts.

Summit claims the cam works with stock springs, and works better with LS6 springs. But I keep seeing (even on this site) that stock L59/862 casting springs are only good for .500" lift. So I'd run PAC 1218's or BTR LS6's if needed, just not certain which is or isn't right.

Seems like the more I try to read, the more questions I come up with. LOL


Appreciate the reply, thanks...

 

OP,

This sounds like an awesome project bringing that Suburban back to life! You're putting in some serious work, and it's great to see the dedication! We’re happy to help dial in the right parts for a durable, warmed-up 5.3 build that’ll last for years. Let’s break it down:

Camshaft & Valvetrain
The Summit Racing Pro LS Stage 1 High Lift SUM-8719R1 cam is a solid choice for your goals. You nailed it—it’s a torque-focused grind with a good balance of power and drivability. It’ll work well with a stock converter or even better with the Trailblazer 4.2L converter. The cam provides a smooth to noticeable idle, depending on where you set the idle speed. At lower idle speeds, you'll get a slight lope, but nothing too aggressive.

For valve springs, at .550" lift stock springs won't be sufficient. Our .550" lift cams were designed around our budget-friendly SUM-174002 LS6-style springs.

Your factory retainers and locks will work just fine with these LS6 springs. Just make sure they look to be in good shape, and you should be good to go.

Pushrods & Lifters? We recommend going with our SUM-HTLSKIT2, which includes Delphi LS7 lifters along with new lifter trays. This ensures everything is fresh and properly secured for long-term reliability. Pushrod length should be verified with a pushrod length checker, but for a stock-style build with that cam, 7.400" is the typical go-to.

Gaskets & Seals
Since you've pulled this down to a shortblock, a full gasket set is the best way to go to make sure everything is fresh and sealed up properly. Fel-Pro and Mahle both have a complete engine gasket set if you're looking for a full refresh.

Oil Pump & Timing Set

• Oil Pump: Our Summit Racing SUM-121170 is a go-to replacement, offering the reliability and performance you need. No need for a high-volume pump here—this will work perfectly for your build.
• Timing set: You could go with a replacement LS2 chain and then add a timing chain dampener kit like the Trick Flow TFS-K30675600 for added stability and longevity.

Head Bolts & Fasteners

• Factory head bolts are torque-to-yield (TTY), which means they stretch when torqued and are technically a one-time use. You’ll need new bolts like our SUM-910210, which are the correct replacement for 2003 and earlier LS engines.
• Difference between 2003 & earlier vs. 2004 & later head bolts:
  • 2003 and earlier blocks use longer bolts in the outer positions (155.5mm) and shorter bolts in the center (101mm).
  • 2004 and later engines use shorter bolts overall, with 100mm outer bolts and 45mm inner bolts.
  • The torque sequence and final torque angle specs are different, so be sure to follow the correct specs for your engine.

You’re on the right track, and we’re happy to help with any other details. Once you get parts in hand, take your time checking clearances and confirming fitment—this will make for a solid, long-lasting build. Keep us posted on the progress, and feel free to reach out with any more questions!

Happy wrenching!

 

Thanks for the kind words and advice. I made the first order over the weekend. Felpro gasket set, ls2 chain, stock volume oil pump. And a few other things. Also over the weekend water tested the chambers/valves and disassembled the heads. Also scraped and scrubbed the living daylights out of them. The old cam is out.

I came across another cam I like, it's on a tighter LSA. Now have to decide which one I'm going to run.
Summit cam
209/217
.550"/.550"
112+1

Cam motion cam
208/214
.553"/.553"
110+4

Got to decide which cam. And pick up the rest of the parts. Springs, lifters, pushrods.


Soon hope to be putting it back together...

 

OP,

Sounds like you’re full steam ahead on this build—always cool to see a project coming together!

On the cam choice, based on what you originally described, our SUM-8719R1 would work well. But if you’re after more low-end grunt, the Cam Motion Titan 1 LS Truck Cam CXM-03-01-0198 would be a better fit. The key difference comes down to the intake valve closing (IVC). The Titan 1 closes at 30° ABDC, while the 8719R1 closes at 36° ABDC. Earlier IVC means the powerband starts (and ends) sooner, which translates to better low-end torque. That said, the Titan 1 still carries power well through the mid-range and top-end. You can still run the same springs, lifters, and pushrods we recommended for the 8719R1. If you wanted an upgrade, our .600" lift beehives would be a good option.

We don't have the Titan 1 in stock. As a similar in-stock option check out our SUM-8728R1. Specs on it are .600/.585, 212/218, 110+3 with -5* of overlap. The IVC of the 8728R1 is 33*. Combining that with the added lift this will be good down low around 2,500 where the Titan 1 is but then carry out even better through the mid-range and top-end with the added lift. The 8728R1 would require our .600" lift beehives or the upgraded .630" lift beehives. You could use the same lifters and possibly the 7.400" pushrods but you may end up with 7.425" pushrods. That's why we always recommend checking pushrod length before purchasing pushrods.


Let us know if you need anything else—happy to help!

 

Is there any chance you could post the cam card numbers for both cams? And while it is much different than why most people nowadays would want to hear a cam idle, I'm interested in listening to each of them to hear how they idle. Stock idle speed in my truck with stock cam is too slow to make enough juice out of my 200A alternator, with all of this running: headlights, both wipers, both flexalite fans, both blower motors, & radio. The idle is already touched up a bit from stock in my tune. So any idea I can get of what the idle quality is of both cams seems helpful. I know they're both small cams and aren't going to sit there and chop away like crazy, but I may not pick the choppier of the two if it means I'll have to turn the idle up more to smooth it out to behave itself and run my electrical demands on full load.

These may be trivial things, but they're considerations I'm making before I do this.

I found one video of the cam motion cam, know nothing about the engine/combo.

And one video of the summit cam, but I know this isn't a "stock" truck gen III 5.3L.

Do you know of any videos of these cams running?

Here's a couple pics of the rig so you know what we're working on...






I truly appreciate your time and help.

 

OP,

Thanks for getting back with us and that's a sweet rig! We appreciate that you want to dive in to truly understand what these options would be like for you. We hear ya on the idle. Our cam calculator will help to illustrate this. Basically, the idle quality comes from the intake valve opening (IVO). The earlier you open the intake the choppier the idle at the expense of idle vacuum.

Titan 1 LS truck 210/218 110+4



Summit 8719R1 209/217, 112+1


As shown in the calculator, the Titan 1 opens the intake valve 4° earlier than the 8719R1 and has slightly more overlap, which contributes to a choppier idle. While neither cam is designed purely for "chop," the Titan 1 should produce a slightly rougher idle compared to the 8719R1 based on its specs.

That said, no two engines are exactly alike—idle quality is influenced by factors like displacement, compression, and exhaust setup. If both cams were installed in the same engine, we’d expect the Titan 1 to require about 200 RPM higher idle speed than the 8719R1 for optimal performance.


Our 8728R1 would have slightly more of an uneven idle than the Titan 1. Here are the calculator specs for it.


If you want to dive deeper into how valve events affect engine performance, here's a great video that illustrates the concepts along with a walkthrough of our cam calculator.

We love talking cams, especially when it comes to valve timing events—they’re what truly define a cam’s performance. These events dictate key parameters like duration, lobe separation, and overlap, shaping how the cam behaves. Our goal isn’t just to sell a cam, but to help buyers make informed decisions!

 

@Summitracing


I was looking for the cam cards so I could see the seat to seat duration for the Cam Motion cam, so I could compare DCR values along with the info you posted. The DCR calculator I use works a little differently than most; uses formulas to figure a dynamic stroke length based on valve events and engine specs before it spits out a DCR value. Searching helped me see where someone claimed Cam Motion told them to generally add 54° to the @ 0.050" duration numbers for the seat to seat numbers. That gives the Titan 1 LS truck cam 262/268 seat to seat duration. I've always understood LS engines to be way different than old school SBC's. According to what we're discussing here ("256" or "260" torque cams on 110 and 112 LSA's) they're not much different at all, they just make more power because they pump air better. Anyways, on to the DCR calculator numbers...

The calculator gave these DCR's:
Cam Motion - 9.02:1 (overlap 45°)
Summit - 8.84:1 ((overlap 41.5°)

From the earlier IVO, the Cam Motion grind has a little longer dynamic stroke than the 8719R1, and you wouldn't think it with the longer overlap of the Cam Motion grind, but with a 9:1 DCR, it probably fills the cylinder more (more BANG), and runs a little higher cylinder pressure too.

I haven't picked a cam yet...still thinking about it. What can you say about the core that the 8719R1 is ground from?

 

Summit cam cores are 5150 USA steel. they have a cool article on here:
https://www.onallcylinders.com/2018/...-cams-factory/