LQ4 + 706 heads + LS3 cam
08-07-2018, 05:50 PM
#1
TECH Apprentice
Thread Starter
LQ4 + 706 heads + LS3 cam I have a 2002 Silverado 1500HD with the LQ4 in it, pushing some decently high miles. This is strictly a daily driver or towing rig, and I occasionally have some pretty steep hills to climb. Between oil changes I知 starting to notice some coolant loss, presumably due to head gaskets, but there may be a possibility of having Castech heads. Either way I壇 like to get a bit more kick out of the truck without spending much money, especially if I値l be pulling the heads anyway. I致e done some research and it seems the 706 5.3L heads are a good combo with the slightly higher compression and people give these things away basically. I ran across an LS3 cam for pretty cheap as well. Would the cam be a decent combo with the 5.3L heads on the 6.0L? I知 not looking to drop $400 on a cam or the same on another set of heads, or flow work. Just looking for a cheap, simple upgrade. Anyone on here ran this combo before?
08-08-2018, 06:01 AM
#3
I think you need to leave it alone. That cam wont work without buying a timing chain cover and moving the cam sensor, and will probably lose low end torque.
The 317 heads on your engine flow better but will give less compression than the 706/862 heads so if you wanna run 91/93 octane you could try some 706 heads and MIGHT gain a small amount of bottom end power, you would go from about 9.4:1 to about 10.5:1
Only cam I would put in it would be an actual aftermarket truck cam and new valve springs/timing chain other than that dont touch the cam.
The 317 heads on your engine flow better but will give less compression than the 706/862 heads so if you wanna run 91/93 octane you could try some 706 heads and MIGHT gain a small amount of bottom end power, you would go from about 9.4:1 to about 10.5:1
Only cam I would put in it would be an actual aftermarket truck cam and new valve springs/timing chain other than that dont touch the cam.
08-08-2018, 10:47 AM
#4
TECH Apprentice
Thread Starter
I disagree on the heads. The 317 heads flowing better is a pretty common misconception, since everyone immediately tags the smaller valve head as inferior. It’s well known that a smaller valve increases velocity up until the point that the valve becomes a restriction, which it isn’t on the 5.3L heads until some pretty significant power gains. The bigger valve will actually hurt power. This is also an engine that spends its life at 1500-5000 RPM with a very low stall converter, so peak numbers become pretty useless here. There are dyno tests showing an average 30-40 hp gain (especially on the low end, where it matters here!), just from changing from 317’s to 706/862’s. That’s well worth the upgrade to me since I’d have the heads off anyway and everyone seems to give away 5.3L heads.
The LS3 cam I’d agree may not be worth the effort, I figured maybe the aftermarket made it easier to convert to a 1-bolt cam. I’d consider a truck cam if I could find a decent enough deal on one, possibly used. I really don’t need much cam since I want to stay with the stock stall and idle quality.
The LS3 cam I’d agree may not be worth the effort, I figured maybe the aftermarket made it easier to convert to a 1-bolt cam. I’d consider a truck cam if I could find a decent enough deal on one, possibly used. I really don’t need much cam since I want to stay with the stock stall and idle quality.
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08-08-2018, 03:29 PM
#8
Hot rod did a cam test if you want to see how poorly that LS3 cam will work for your goals. I believe it loses out badly below 4k then picks up till the pull is stopped.
The heads would help with low end and the compression bump will add power everywhere, I'm sure you already know.
But with a heavy truck and high compression and pulling up hills etc, you'll need high octane fuel and a really good tuner.
If you consider a cam, consider a drop in truck cam, they pick up power in lower rpm ranges over other cams (stock and aftermarket). Any of the OE LS cams lose power down low compared to the truck cams so any of them would be moving backwards for your goals.
The only way to get the LS3 cam to work is to put a new from cover on the motor with a cam sensor in it, you can get a 1x gear for it but you still have to read the gear, your LQ4 reads off the back of the cam and there's no conversion to put a tone wheel on the rear of a cam so the conversion part has to be off the front of the cam.
The heads would help with low end and the compression bump will add power everywhere, I'm sure you already know.
But with a heavy truck and high compression and pulling up hills etc, you'll need high octane fuel and a really good tuner.
If you consider a cam, consider a drop in truck cam, they pick up power in lower rpm ranges over other cams (stock and aftermarket). Any of the OE LS cams lose power down low compared to the truck cams so any of them would be moving backwards for your goals.
The only way to get the LS3 cam to work is to put a new from cover on the motor with a cam sensor in it, you can get a 1x gear for it but you still have to read the gear, your LQ4 reads off the back of the cam and there's no conversion to put a tone wheel on the rear of a cam so the conversion part has to be off the front of the cam.
11-05-2018, 07:38 PM
#12
Teching In
I didn't do that build but I am going to do the top end on my 03 1500 HD, 101k mi., LQ4 with 706 heads, TBSS intake, TSP stage 3 truck cam, Speed Eng shorties, duals on a Magnaflow (already on), 91 tune. I was talking with my machine shop guy and he agrees with the same logic, smaller valve more velocity, he says they used to do it with the 5.7 w/ 5.0 heads.
Last edited by matts01z71; 01-01-2019 at 06:46 AM.
11-13-2018, 08:56 PM
#13
I didn't do that build but I am going to do the top end on my 03 1500 HD, 101k mi., LQ4 with 706 heads, TBSS intake, ($130.00 at wallyworldweb) Summit stage 1 LL truck cam/springs, Speed Eng shorties, duals on a Magnaflow (already on), 91 tune. I was talking with my machine shop and he agrees with the same logic, smaller valve more velocity, he says they used to do it with the 5.7 w/ 5.0 heads.
11-14-2018, 08:27 AM
#14
We’ll never mind, I had a stock lq9 I dropped in instead.
I don’t think I want to put close chamber heads, 706 style, on a daily driver as the compression may be kind of high.
Around 11-1 from what I read. I know that’s nothing now a days, but for a daily, I’d rather be safer.
I actually wanted to put the lq4 so I could run 87 all day long, but I said f it and did the lq9.
I may have the lq9 tuned on 87 then on 93 to see the difference once the swap is done.
Its a stock lq9, stock intake, Tb & truck man, 1-7/8 speed engineering headers, 2.5” dual exhaust in an 87 Monte Carlo.
with a 700r4 and a 9” which will rob some power.
Once the swap is done and get the bugs or issues fixed on this swap, ill decide what route is next for the car.
T56, heads and cam selection as this car has ac I need to put back into it.
I don’t think I want to put close chamber heads, 706 style, on a daily driver as the compression may be kind of high.
Around 11-1 from what I read. I know that’s nothing now a days, but for a daily, I’d rather be safer.
I actually wanted to put the lq4 so I could run 87 all day long, but I said f it and did the lq9.
I may have the lq9 tuned on 87 then on 93 to see the difference once the swap is done.
Its a stock lq9, stock intake, Tb & truck man, 1-7/8 speed engineering headers, 2.5” dual exhaust in an 87 Monte Carlo.
with a 700r4 and a 9” which will rob some power.
Once the swap is done and get the bugs or issues fixed on this swap, ill decide what route is next for the car.
T56, heads and cam selection as this car has ac I need to put back into it.
10-06-2019, 01:23 PM
#15
Reviving an old thread because I'm curious if anyone's actually done the LQ4+5.3 heads+LS6/LS2 cam and has some numbers? Those are the only 'drop in' hot factory cams into the truck motors, correct? I have some parts collected and will be swapping an LQ4/4L80 into my 83 Cutlass Cruiser to replace the carb'd LR4/TH350. Seems like the best low budget recipe to me.
10-07-2019, 02:42 PM
#16
That would work real well. But summit has some nice cams for only $289 that you would pick up a good 50 hp, or more depending on the cam you chose over the ls6 cam with so I would seriously look into spending just a little more money for a hell of a lot of gain. Pushrods and valve springs to go with it will set you back a bit but you'd already need to get at least LS6 valve springs to run the LS6 cam so not buying those will offset the price of the cam setup a hair. Plus not buying a LS6 cam.
If you don't buy the LS6 cam and springs you will save about $200 or so toward the summit cam/springs/pushrods and gain around 50 hp. There isn't another way ever you'll get 50-70 or so hp for around $300 (300 more than going LS6 cam)
If you don't buy the LS6 cam and springs you will save about $200 or so toward the summit cam/springs/pushrods and gain around 50 hp. There isn't another way ever you'll get 50-70 or so hp for around $300 (300 more than going LS6 cam)
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10-08-2019, 08:57 AM
#17
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Reviving an old thread because I'm curious if anyone's actually done the LQ4+5.3 heads+LS6/LS2 cam and has some numbers? Those are the only 'drop in' hot factory cams into the truck motors, correct? I have some parts collected and will be swapping an LQ4/4L80 into my 83 Cutlass Cruiser to replace the carb'd LR4/TH350. Seems like the best low budget recipe to me.
As 00pooterSS said we have some great camshafts at competitive prices that would work well for you. We would recommend either the stage 1 "Ghost Cam" kit or the stage 2 cam kit for your application. The stage 1 will have a noticeable lope at low idle speed but smooths out around 900 rpm and it's easy to tune. This cam will make excellent power and is stable up through 7000 rpm with the included beehive springs. To take full advantage of the power a 2500 stall converter is recommended but not required.
The stage 2 cam has a steady lope but tunes well and is easy to live with. This has a wide powerband that pulls strong past 7000 rpm with the included beehive springs. To take full advantage of the power a 2500 stall converter is recommended but not required. These include the cam, springs, valve seals, harmonic balancer bolt, timing cover gasket and seal, water pump gaskets, oil pump o-ring and valve cover gaskets.
With either of these cams and the use of stock rocker arms we recommend using a pushrod length checker, but in most cases a 7.400 in. or 7.425 in. pushrod will work. It's particularly important to check pushrod length if the cylinder heads have been milled. If you wanted to check for pushrod length and do not already have a pushrod length checker we offer the Trick Flow TFS-9501.
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10-08-2019, 11:21 AM
#18
Thanks for the reply. I love that you guys have a dept that replies to forum questions.
I found an LS6 cam for $80. But for another $200 I may just go ahead and grab that. Got a link to one of these $289 cams?
I just picked up an LQ4/4L80 for free and have a 5.3 I was taking apart to rebuild. Might as well utilize the heads and install a cam at the same time seeing as it looks like I sold the 4.8/TH350 carbureted setup in my wagon..... Thanks for the suggestions.
I found an LS6 cam for $80. But for another $200 I may just go ahead and grab that. Got a link to one of these $289 cams?
I just picked up an LQ4/4L80 for free and have a 5.3 I was taking apart to rebuild. Might as well utilize the heads and install a cam at the same time seeing as it looks like I sold the 4.8/TH350 carbureted setup in my wagon..... Thanks for the suggestions.
10-08-2019, 11:57 AM
#19
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Thanks for the reply. I love that you guys have a dept that replies to forum questions.
I found an LS6 cam for $80. But for another $200 I may just go ahead and grab that. Got a link to one of these $289 cams?
I just picked up an LQ4/4L80 for free and have a 5.3 I was taking apart to rebuild. Might as well utilize the heads and install a cam at the same time seeing as it looks like I sold the 4.8/TH350 carbureted setup in my wagon..... Thanks for the suggestions.
I found an LS6 cam for $80. But for another $200 I may just go ahead and grab that. Got a link to one of these $289 cams?
I just picked up an LQ4/4L80 for free and have a 5.3 I was taking apart to rebuild. Might as well utilize the heads and install a cam at the same time seeing as it looks like I sold the 4.8/TH350 carbureted setup in my wagon..... Thanks for the suggestions.
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G Atsma (11-10-2019)