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I have a LM7 5.3 that came factory in my 2000 SIlverado and has 108k miles.
I am the original owner since new and it has been pampered and well taken care of.
I am currently in the process of replacing the 862 cylinder heads with new 862 heads.
I had a coolant leak on the drivers side head around the center head bolts between cylinder 1 & 3 and 3 & 5.
I am going to replace the lifters and trays, while in there, with LS7 Lifters and Guides, 12499225, & 12595365.
I have a friend with a camshaft and valve springs from a 2005 GTO 6.0, and he is willing to let them go for $50.
He only had 8,000 miles on his engine when I helped him swap the cam so it is in excellent shape.
I already have a very mild tune on the truck and my tuner said he could tune it for the GTO cam specs easily.
My questions are:
1. Will the cam from a 2005 GTO 6.0 physically work in my 2000 LM7 5.3?
2. Are the valve springs from the 2005 GTO 6.0 similar to the LS6 springs everyone recommends?
3. What is the probability my original push rods will be the correct length?
4. The cam specs should be 204/213, 520/521, 116LS. What kind of gain am I looking at? (my Silverado is bone stock except tune which will be changed to accommodate the new cam)
5. Are there any issues I am overlooking with this cam swap I have not mentioned?
This truck is my only daily driver and I am lucky enough to borrow my Dad's truck until I finish but I want to get this project done as soon as possible to get his truck back to him.
Any tips, hints, or recommendations are greatly appreciated.
1. Will the cam from a 2005 GTO 6.0 physically work in my 2000 LM7 5.3?
2. Are the valve springs from the 2005 GTO 6.0 similar to the LS6 springs everyone recommends?
3. What is the probability my original push rods will be the correct length?
4. The cam specs should be 204/213, 520/521, 116LS. What kind of gain am I looking at? (my Silverado is bone stock except tune which will be changed to accommodate the new cam)
5. Are there any issues I am overlooking with this cam swap I have not mentioned?
This truck is my only daily driver and I am lucky enough to borrow my Dad's truck until I finish but I want to get this project done as soon as possible to get his truck back to him.
Any tips, hints, or recommendations are greatly appreciated.
1. It might not, unless it has the cam sensor rings on the back of the cam like the Gen III cams all do. See #5 below.
2. Close enough
3. 100%. All LS pushrods are 7.4"
4. I would estimate about 50HP. Actual cam specs are 204/211, .525/.525, 116LSA. It's the same grind as the early LS6.
5. As I said above, the LS2 is an early Gen IV engine, and might not have the cam sensor rings on the cam. If not, you can get a later front cover with the sensor plug and a timing set with what's known as a 1x timing sprocket.
I know the GTO is a 2005 model, but my buddy claims the engine is a LS1.
He said when he ordered the camshaft he replaced the original with he had to order one for an LS1.
I will have to take a look and see if his cam has the sensor ring near the rear of the cam.
I have a pretty good memory but my buddy cant normally remember what he had for breakfast, much less what part he ordered 12 years ago.
The good news is that it is a LS1 cam with the cam sensor near the rear of the cam.
The bad news is that the part number on it is 1721 S 12 4110.
# 1721 specs
196 / 201 . lift 467 / 479 LSA 116
Not enough gained to bother with it.
my factory cam specs:
190/191 .466"/.457" 114 LSA
#1721 is 196/207 and the correct duration of the 5.7 and it’s also the same cam for the Lq9.
Hotrod did a cam swap test and the LQ9 #1721 cam was worth 40hp and tq over the stock 191/190 5.3 cam. It had NO loss in low end tq and requires no computer tuning. I know bc I picked up 2 for cheap for my 5.3 swaps. It’s a stealth cam with no loss in low end but all top end 3500-6k. I think it’s fully worth it. You don’t need springs but I do the Ls6 bc they are cheap and better than the Truck springs.
A lot of people over look them but they are cheap easy power bumps with rock solid low idle. I also did one in my dads 5.3 motor and it runs good.
Technical Notes: Stock cam for 2002-2006 LQ9 and 2001-2004 LS1 engines
From Hot Rod cam shootout:
Contrary to popular belief, the L33 cam is not the same as the LQ9 grind. The L33 was essentially a high-lift version of the LM7 with a few extra degrees of duration. In terms of power, the L33 offered additional power over the LM7 cam but did not increase power as much as the LQ9. As expected, there was no change to idle vacuum, and cranking compression was within a few psi of the LM7. Though the L33 offered more power than the mild LM7, it’s hardly worth the effort. Grab one of the hotter factory (or Crane) cams if you are going to upgrade.
Im seeing 196/207 and multiple sources say the same thing. You might be looking at the LQ4 cam which was smaller. Also your cam specs said LS1 and LS9 cam, not LQ9. The LS9 cam is 211/230.
And also in this screenshot which shows all the factory cams. The LQ9 cam is a small upgrade that shows mild gains with no tuning, in sure some tuning could increase power slightly and since u have a mild tune it’s prob good to go.
The zero loss in power (-8ftlb at 2500) is like nothing and thus would pull well on the highway. Most aftermarket cams don’t increase power that low in the range. Also a lot of people don’t run 5.3s in just trucks so I spend quite a lot of time between 3-5k in a lighter car where the LQ9 cam would work better. Sure not as much as an aftermarket cam but those are $300-400 and the. $150+ springs and it’s hard on parts. I could easily crank boost 1-2psi and make the same power as a more expensive cam would have with lower boost. i also spin to 6k in my 5.3 when gunning it on the highway entrance ramps and going hard on the street. Cheap, increased power, no tuning issues, easy on the valve train and works with boost sounds like a good investment to some.
Smaller motors require rpm to create power. It’s why longer stroke big cube motors create more low end power.
A small 70/65 turbo would and could put 400+ftlbs below 3k and already be in boost. I know I was in boost on my 5.3 before 3k with a 76/65. The smaller turbo or even a smaller exhaust size would spool even quicker and create stupid power even lower. Below 3k just isn’t enough for 325 cubes to do anything with it. Increase displacement via cubes or boost and it’s a different story.
The 1721 cam is exactly the one to run of the GM options for heavy truck with no stall converter. If you have the money for a Cam Motion drop in stick; the 205/210 is about your best option for daily driving
Also milling those newer 862 heads about .025”-.030” will increase the cylinder pressure and help your low end torque. Compression helps TQ @ all rpms
SDPC also has a small truck cam 205/210 .525/.525 lift I believe for $300 that I was looking at ($300 is still $300 compared to a $50 LQ9 cam). It would work well being such a small cam to keep the power band low. I doubt you would gain anything below 2500rpms since its very low and not alot of rpm to notice changes in flow.
The reason I was even looking at camshaft options is because I am replacing my heads due to one being cracked.
My heads are 862 casting but not the ones from castech which surprised me that one cracked.
The truck was never abused and has been very well maintained since new.
The machine shop is taking .020 off my replacement heads. They said they were not comfortable taking any more off.
My other car is a 1.9 VW diesel. Highly modified. Factory it was 90 hp 198 tq, now it dynos out at 215 hp 398 tq. Very fun to drive. Snapped a few cv axles so I have to be careful, but it is fun.
Milled heads, tune and electric fans would be a nice bump in the entire rev range.
On my 2004 truck I got a radiator and fan setup from a 07-13 truck, went to the junk yard and got a front end wiring harness from a 07-13 truck and pulled the fan wiring and fuse block out of it. The fuse and relay block for the fans snaps onto the side of your existing fuse box, then all you have to do is pin the two control wires into your pcm wiring and have the tuner download a fan file into your computer. With that setup no drilling or anything is needed. Everything bolts right in and is controlled by the pcm on full OE parts too.
04-04-2018, 09:58 PM
05 GTO 6.0 cam and springs in a LM7? 
