So I bought a 2000 Silverado. The tires are bald, the suspension is clapped out, the master cylinder needs to be rebuilt. So naturally my first concern is which cam will really wake the motor up. It still needs to do truck things, I'd just like it to do them with a little more ambition. This is my preliminary spreadsheet, wondering if I'm down the right path for cheap speed with headers, cam and a tune?
The Jegs cam is very mild. I've used it in ~3 builds now. Lobe profile is VERY lazy.
The trick flow cam is a decent cam but the lobe profile is still pretty bad. Its made by Elgin which also makes the JEGS cam.
The rest of them all appear to be cams you picked from magazine articles.
You might want to decide how you want it to behave and drive. Big cams like the Comp 54-454-11 are going to be really bad to try to drive in a heavy vehicle. It'll also idle extremely high and be very loud.
This seemed interesting;
http://www.hotrod.com/articles/ls-cam-test-comparison/
That smallest-of-three Crane cam that they tested seems interesting for a truck owner. Perhaps, though, money would be better spent on a good exhaust with new cats for your truck? I don't believe the factory manifolds are that well liked and the rest is built for cost and noise concerns first.
Sloppy stage 1, TFS stage 1 cam, in my burb is a lazy mofo. My av in the stock stick is way more responsive, but I haven’t dyno’d either for a definitive answer yet.
If and when I do can my Avalanche, it’ll be the sloppy stage 2 or spend the coin for a custom ljms cam. Because turbos.
If you have more than 75k miles on the motor replace the springs anyways.
Ranger50 said:Sloppy stage 1, TFS stage 1 cam, in my burb is a lazy mofo. My av in the stock stick is way more responsive, but I haven’t dyno’d either for a definitive answer yet.
If and when I do can my Avalanche, it’ll be the sloppy stage 2 or spend the coin for a custom ljms cam. Because turbos.
I can't believe bandwagon cams are such a thing now. Especially when Matt even says he doesn't know anything about cams, and John picks lobes straight out of Comps catalog or mixes and matches the intake and exhaust lobes from shelf Comp cams and calls them custom.
OP, for less than $400 will get you stainless long tubes and Y-pipe for your truck from Speed Engineering. Their headers are excellent. That would be my first mod. Maybe a K&N intake afterwards, it won't get you much power, but you'll see good benefits after a cam install. If its 2wd, swap the gearing out to 4.10.
LM7 5.3L Engine Upgrade Guide: Expert Advice for LM7 Mods to Maximize Performance - I like this article. First upgrades make sense. They recommend a cam after exhaust, intake, and ecu tuning.
More research says 799 heads are on the cheap end at $250 used. If you want to do a head swap that'll only help if you're doing a cam as well. I think heads with a casting number 243 are similar. If you want to make a good head better enlarge the intake valves and have the bowls blended during the install of the valves. You can either shave/deck the head or adjust the head gasket thickness to increase compression. Info below from another thread:
"The #799's are the same as the #243 LS6/2 heads. Standard 24N Stainless valves, 2.00I, 1.55E, 210cc intake runner. The come standard on the L33HO 5.3L and 07+ 5.3L's.
My 08 Sierra has the #799's."
"RPO L33 FOR CHEVROLET SILVERADO AND GMC SIERRA
The Gen III Vortec 5300 is available in a new lighter, higher output variant optional on some 2005 Silverados and Sierras. RPO L33 will be introduced in short bed, extended cab versions of these pickups. The L33 features an aluminum engine block, new cylinder heads and a high-lift cam. Torque will increase, and horsepower is expected to exceed 300 in final production trim.
One of the L33’s distinguishing features is its engine block. As with the 2004 LM4 Vortec 5300, the L33’s foundation is a cast-aluminum block with pressed-in iron cylinder liners, similar to the block used for GM Powertrain’s LS1 and LS6 car V-8s. The L33 block is exceptionally light; as a result, a fully dressed L33 is 100 pounds lighter than cast iron-block Vortec 5300s (RPOs LM7 and L59).
The L33 takes its cylinder heads from the LS6. Originally developed for the Z06 Corvette, these heads improve airflow in and out of the engine. With their pent-roof combustions chambers and new flat top pistons (the pistons in other Gen III Vortec 5300s have a slight sump in the piston deck), the L33’s compression ratio increases from 9.5:1 to 9.9:1. This increase improves the engine’s volumetric efficiency yet still allows it to achieve full power with regular grade gasoline.
Finally, the L33 is equipped with a higher-lift camshaft. Maximum valve lift increases from 11.6 mm on the LM7 and L59 to 12.5 mm. The new cam and compression ratio are the primary sources of the L33’s increased horsepower.
The L33 camshaft and cylinder heads were developed in conjunction with the new Gen IV Vortec 5300 (RPO LH6). The design objective was more horsepower for customers who need it, without requiring a step up to the Vortec 6000 (and an increase in operational costs). RPO L33 expands GM Powertrain’s lineup of Vortec V8s and gives GM’s truck customers even more flexibility and choice.
The L33 Vortec 5300 will be built at Powertrain’s Romulus, Mich., engine plant. With its introduction, Powertrain will cease production of Vortec 5300 RPO LM4. The Buick Rainier, Chevrolet Trailblazer EXT and GMC Envoy XL, previously equipped with the LM4, will now be powered by the Gen IV Vortec 5300 with Displacement on Demand. The 2005 Chevrolet SSR will be powered by the new LS2 truck V-8."
If you *have* to have a cam swap...
That's a lot of info on an engine that he doesn't have.
Swapping 799/243 heads onto an LM7 lowers compression to ~9.2:1. Has been proven to lose power/torque despite the better head flow and larger valves. You would have to mill them .030" in order to get back to stock compression and see any gains. Even then, you're looking at spending ~700+ on heads/springs/machine work/pushrods for a 10 HP gain, and thats if you do the labor yourself.
In reply to AwesomeAuto :
No crazy lope, no high idle. Looks like I'll just search around for a used exhaust, do the supporting mods first, though the 4.10 gears seem like a great starting point as well.
My personal choices for cams for a truck setup if you want something that will run/idle good and make excellent torque:
1. Isky Triple 12. 212/212 112 LSA. Excellent torque and all around power. Idles good. Good luck finding one. They are like Unicorn's horns.
2. Howards 190315-08. 210/214 108 LSA. "Cammed" idle, but not too bad. INSTANT torque and throttle response. Won't make huge gains up top, mostly a torque cam.
3. Lunati 20540710. 212/218 113 LSA. Typical truck cam specs, but will work with $60 LS6 valve springs. Makes more power up top than other 2, won't make near the torque.
After those, I would probably default back to the typical LS cam companies that offer a few stages to cover a broad range.
1. BTR Stage 1/2 truck cams.
2. Texas Speed Stage 1/2 5.3 truck cams (112 LSA).
3. ETC.
Thanks Awesome. I've been eyeing Texas Speed stuff, mostly because they're only 30 minutes away...
Any of those cams with Speed engineering 1 3/4" headers and Y pipe setup, 4.10 gears and a good tune will make a significant difference in performance.
If you have all of the specs of the lobs on the Isky Triple 12, can you not just go through Comp's lobe catalog and "build" a copy or something extremely close to the same? This is assuming there isn't a cam like that already on the shelf with someone else.
You can use another companies lobes to get the same .050" duration and LSA, but you won't get anywhere close to the same lobe profile. It would be like expecting 2 500 HP cars to perform exactly identical with no other info at all. I don't think the Isky cams give their .200" lift duration out for that cam to determine the lobe profile.
The closest thing would probably be a pair of Comp 3709 lobes on a 112 LSA, although I can't remember off the top of my head how much advance is ground into the Triple 12, either.
Yeah, I came here to say BTR stage 1, LS6 springs, 1.75" longtubes and a tune. Skip the heads unless yours need to come off. If it needs pistons or bearings, go to GenIV flattops at that time. Just my .02
I got the Airaid modular intake tube (not the whole intake) and dryflow filter on ebay last year for about $125 shipped, then had my truck (02 L59 Tahoe 2wd) tuned by BlackBear Performance. Happy with the modest results thus far. Eyeing an electric fan swap (already coded in the tune) and headers next year. Hadn't seen the Speed Engineering ones, much more friendly pricepoint than ARH...
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