Hey Guys,

I have a 5.3 from a 2000 Yukon XL that I'm going to be swapping in to my '89 K5 and am trying to get a game plan going. I'm planning on doing a really mild build since I'm on somewhat of a budget and am located in CA so long tubes, cats delete, LSXRT intake, and monster cams are out of the question. Just the stock truck intake and cats with LS3 exhaust manifolds from a C6 for frame clearance.

I've been reading up on here and PerformanceTrucks and after talking to a few of our sponsors I'll likely be going with a smaller 206/212 cam like the BTR Stage 1 Truck Cam, Cam Motion 5.3 Stage 2 Cam, or similar custom grind since I'll need as much low end torque as possible for my heavy truck and will rarely wind the engine up to 6000 rpm. What I'm up in the air about is whether or not I should send my stock 862 heads to WCCH for their Stage 2 package (CNC port with 1.950"/1.570" valves) or Texas Speed for their PRC Stage 2.5 package (CNC port with 2.02"/1.575" valves). They seem like a good value for $900-950 but I'm not sure if it'd be worth it in the long run with such a mild build like mine. What do you guys think?

The end goal for the truck is to be a fun DD and occasional trail rig with better performance, reliability, and fuel economy than the 350 it's replacing and yes I've already talked to the smog ref's about the swap and know about carrying over the evap system along with all the smog stuff from the newer vehicle lol. The 5.3 has 146xxx miles and runs great (I have the complete wrecked donor) but even if I only do the cam swap I'll still be replacing the springs, push rods, timing chain, and oil pump for peace of mind. The K5 still has the stock 3.42 gears and 32" tires (for now) and the engine will be mated up to a 4l80e with stock stalled TC from a 6.0 Silverado in case needs that info.

Any advice is appreciated. Thanks, Anthony.

 

That 5.3L seems to be the low 9.5:1 SCR engine with dished pistons and a 270hp rating, so yes you would benefit from a higher static compression ratio and better flowing heads even if you kept the stock cam. I'd at a minimum have the stock heads milled to get the SCR up to at least 10:1, but no higher than about 10.5:1. That would get the DCS up and give a nice little bump in low-end TQ, and overall hp, and be very budget friendly.
I would say you're right about where you want to be as far as cam specs.
Another cam option is the Comp Cams #54-408-11(206/212 112lsa+2, lift .515"/.522"). Furthermore, you can get this cam for as low as $355.
http://www.ws6project.com/user_stor/...e-rpm-206-212/

 

I'm running the Cam Motion stage 2 cam you are looking at and definitely recommend it.

For heads, it will depend on what you want from the truck....it would benefit from ported heads or more compression but at the cost of having to bump up to premium fuel as well as the additional cost of port work, head bolts, gaskets, etc.

That cam works excellent in an otherwise stock engine as it was designed to do. Mine will run fine on 87 still but moves partially into my low octane timing tables...so it runs better on 89 octane with the tune I have built for it. I am using a modified ls1 car timing table, so nothing too aggressive. It could be tuned to run on 87, the better fuel was my choice.

If I were in your shoes, I would skip the head work unless you are pulling them anyway and didn't mind running the more expensive fuel...in which case like 99Bluz28 suggested I would mill them a bit.

For a mild build like yours I would not be able to justify the $1000+ for fully ported heads. But if you do, I would ask Kip at Cam Motion about grinding you a modified version of his truck cam with some more lift to take better advantage of the port work you paid for.

But overall with the limits to intake manifold and exhaust you have, I am not sure you would get your monies worth from a full blown port job and would probably see most of the same gains from a mild cleanup port and valve job. I'm not an expert so others might chime in and contradict me which is fine.

 

Thanks for the replies so far guys. I wasn’t planning on milling the heads to bump up the compression ratio mainly since I don’t want to limit myself to the higher grade fuels. Some of gas stations where I camp, wheel, and hunt don’t carry anything besides regular 87 octane and diesel and I don’t want to deal with pinging or poor performance when I’m way out in the sticks lol. If this were a street/city only truck I wouldn't have a problem running premium fuel and milling the heads for the extra compression.

99Bluz28 - That cam shaft from Comp you mentioned is almost identical to the XFI Extreme Truck (#54-450-11) cam that I was recommended by one of their reps. The specs on that one were 206/212 .513”/.520” on a 115 LSA. I wonder how they would compare and what’s so different besides one being marketed for the trucks and one for the cars…

The main reason I was mentioning the BTR and Cam Motion cams was because I found couple of good write-ups/reviews from people using them in similar trucks (or at least engines) as mine but I could never really find anything about those specific Comp cams. I’m not 100% sold on any particular cam though so if there are any more recommendations feel free to throw them out there as well.

Thunderstruck507 - I’m glad you saw this thread since your review on PerformanceTrucks really got me looking at the Cam Motion 5.3 Stage 2 cam shaft. You’re also spot on about negative side of bumping the compression up and having to use higher grade fuels which is why I’m hesitant to go through the extra effort for the heads. If I do send them out I would likely just have the valve job and CNC porting done but wouldn’t have them milled at this point (besides having the surface checked and decked).

I’m a realistic guy and know my 5.3 with the stock truck intake and LS3 exhaust manifolds won’t be putting down 400+ hp to the wheels or anything crazy like that but I’d be stoked if I could squeeze out 300 hp or so. I plan on stroking this engine out to 346/5.7 whenever it’s due for a rebuild so maybe I’ll hold off on any head work until then…

 

Why not find a set of 243/799 heads in good shape. Clean em up and mill .030" to get around 9.75 compression and you could still use 87 with that 206/212 camshaft. Even without porting them the larger valves and better runners will make more power than the current heads and for half the cost of the CNC work. 400 for cores and 100 for milling.

 

That cam shaft from Comp you mentioned is almost identical to the XFI Extreme Truck (#54-450-11) cam that I was recommended by one of their reps. The specs on that one were 206/212 .513”/.520” on a 115 LSA. I wonder how they would compare and what’s so different besides one being marketed for the trucks and one for the cars…


The Comp #408 when compared to the#450 will have a little bit more DCR for better low-end power, and a slightly lower IVC for a power band around 70-100 lower in the rpm range, Other than that they both use the same lobes, and will run very smooth in you engine. So I'd recommend going with the #408 since that'll give you the most of what your wanting, better low-end power.

 

another option would be an ls6 cam, can find them pretty reasonable

 

Thanks for the replies fellas.

I had looked in to the LS6 cam and everything I had read showed it making better high end power but actually had less in the low end where I need it than the stock LM7 cam. The LS2 cam looked to be better all around from what I remember reading but required changing a handful of other parts to work which basically made using a used LS2 cost almost the same as one of the new truck cams I was looking at.

Thanks for that detailed response. I'll definitely keep that cam shaft in mind when it comes time to order everything.

I had thought about picking up some 243/799 heads but the cheapest I've been able to find used ones locally has been in the $5-600 range and adding the cleanup and milling work to that would put me in the same price range as porting my stock 862's. I've seen a few people selling them in the classifieds here for $350-450 but they get snatched up almost instantly.

The other reason I was hesitant to go that direction was because of all the mixed info I've been reading about valve shrouding with the larger valves in the 243's once you start milling them down and bolt them on top of the small bore of the 5.3... If I could find a good deal on a set of those heads I'd be down to try that I'd still need to find a good machine shop to do the work. There are a couple machine shops nearby but none that specialize in LSx engines or that I've been able to verify the quality of work so I'd most likely have to ship them out to a quality shop to make sure things were done right. If anyone knows of any good shops in the Sacramento area let me know lol.