From reading on the forums here I know an LS3 head will bolt up to an LS2. I'm told they are a far better head and its why LS3's put down the numbers they do. Is this true?
My other question is.... Is it worth buyin a set of LS3 heads and having them ported or should I stick with my stock LS2 heads?
Also what other differences do they motors have besides a larger bore?
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06 Spice Red GTO - A4, 18 inch wheels
13.56 @ 103.24, 2.02 60ft. (Bone Stock)
Volant CAI, Ported Intake and Throttle Body, Tuned by Rian
LS3 or L92 heads do indeed flow better and make more power than the stock LS2 heads. The intake ports are rectangular instead of cathedral shaped like the older LS1/LS2 ports. Texas Speed sells ported L92 heads if that's what you want.
I don't know all the differences, but the LS3 is 6.2L (larger displacement), plus the heads, rockers, intake manifold, and injectors are different, etc. etc.
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2004 torrid red with red interior A4 GTO (1 of 499)
and no need to port really there huge as is. Just make sure you cut 030 to get c/r back, and be careful with ptv clearance with big cams unless you want to fly cut
Yeah they do. And for $533 plus springs, they are the performance buy of a lifetime.
I have been hearing they bolt right up and give you 30 more hp over the LS2 head unported. Is it worth porting an LS3 head? I wanna maintain drivability and keep it a sleeper somewhat so I wanna hold off on the cam. Will I see these results?
If I can make 30-40 extra HP by slapping on LS3 heads and a ported LS3 intake, I think its worth it.
Yeah they do. And for $533 plus springs, they are the performance buy of a lifetime.
Where can I get them for $533? I will buy them this week!! After its all said and done its worth doing a swap to an LS3 head. And almost cheaper and easier than doing a cam?!
bore size is the big difference really, the 6.2L blocks do have some more structural strength but for a n/a build don't think it would matter
LS2 = 4.000 bore
LS3 = 4.065 bore
yes it makes a big difference in actual flow into the cylinder with that extra .065"
Ebay is the place to look for the good deals on L92s
You'll need intake rockers and the support stands for them, these can be purchased new from the dealer for fairly cheap. $11 each ($88) for the rockers, and the stand I think are about $6 each if I recall (you need 2)
Personally, I'm not sure you'll get 20-30 rwhp just swapping heads with the stock cam. You'll get something but a more aggressive cam will really start to shine with these heads. Be an interesting experiment to see the power gain from heads on stock cam though.
Is it worth porting a LS3 head? probably not with a stock cam. Spending some $$ to have a performance valve job would be a good idea, and having them milled .030" like vcncys suggested.
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I have been hearing they bolt right up and give you 30 more hp over the LS2 head unported. Is it worth porting an LS3 head? I wanna maintain drivability and keep it a sleeper somewhat so I wanna hold off on the cam. Will I see these results?
If I can make 30-40 extra HP by slapping on LS3 heads and a ported LS3 intake, I think its worth it.
If that's the case, then your otherwise stock LS2 would be making the same numbers as an LS3 despite the latter have larger displacement.
The eBay link is for L92 heads. You need to mill them .030 over to get the compression ratio back to stock. Those also have the crappy 2-piece valves, which means you need to get new valves. LS3 heads have good valve in them from the factory.
Are these good heads? Yes, they're great, but they are not for everybody. When all is said and done, you will be spending about the same as you would for some Patriot heads or comparable ported 243s.
Where can I get them for $533? I will buy them this week!! After its all said and done its worth doing a swap to an LS3 head. And almost cheaper and easier than doing a cam?!
With all the crap you gotta buy with those heads (Intake, fuel rails, dif injectors, 8 rockers, 2 stands, send them to head shop for milling if you want to keep compression...etc) and then watch your PTV if you want a big cam Im thinking it would be more beneficial to have the stock 243s professionally ported, keep the larger compression, keep the bigger cam without flycuts or PTV issues...etc.
I'd love to see a apples to apples comparo between pro ported 243s (...and no, I dont mean gouged out with a dremel Patriots, PRO ported 243s like FTI) and non ported/non milled LS3/92/76s on a LS2 engine with a mid-range or big cam.
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Nah from what I learned the bore size is too small. Gotta be 4.00 or larger....
You guys might think I'm crazy but I talked to a buddy of mine and I can get a set of bare LS3 heads for a $150 a pop. I can have them milled and put what ever valves I want on them. It will prolly cost me around 700 or 800 bucks in the end but I will have I think a pretty decent set of heads.
I wanna keep the stock cam only for drivability and a sleeper setup.... which I think are two great reasons.
What confuses me if I do this swap the only difference really would be displacement as far as an LS2 and LS3 go correct??
And LS3s make 30 more HP than LS2's right??? So whats to say I wont get the 30-40 extra RWHP with the ported LS3 tuned??
My plan is with full bolt-ons and this setup I should be able to put down somewhere between 410-420 to the wheels I'm hoping.
What really tickles my sphincter is it will sound pretty much stock besides an exhaust and drivability will be like it is now. No cackle and people will think they're racing a pig with some bolt-ons??
Sorry guys if I'm retarted please tell me..... Wanna hear everybody's opinon on this.....
Porting doesn't automatically get you more power. If you don't have the necessary components (like a larger camshaft), it can actually hinder performance. I would recommend doing nothing more than a mild cleaning of the ports if you're going to do anything.
there's nothing wrong with the valves in the Ebay link I posted BTW. They will work on any setup unless you want 7000rpm. I'd say the average LS2 won't be going more than 6500 tops. Max power will be around 6-6200 anyway.
LS-WON, the cubes, increased bore size, and bigger cam of the LS3 are what gets it the power. Just putting the heads on your stock LS2 short block I don't think will result in the same thing. Not trying to discourage you from trying...I'd be interested to see.
A fair price for milling would be around $60 per head from my experience. Deburring afterwards is a nice touch to save your hands from countless slices
With all the crap you gotta buy with those heads (Intake, fuel rails, dif injectors, 8 rockers, 2 stands, send them to head shop for milling if you want to keep compression...etc) and then watch your PTV if you want a big cam Im thinking it would be more beneficial to have the stock 243s professionally ported, keep the larger compression, keep the bigger cam without flycuts or PTV issues...etc.
I'd love to see a apples to apples comparo between pro ported 243s (...and no, I dont mean gouged out with a dremel Patriots, PRO ported 243s like FTI) and non ported/non milled LS3/92/76s on a LS2 engine with a mid-range or big cam.
I found lots of deals on Ebay for intakes with rails and injectors all connected for under $300. I looked up under completed auctions as well so that is what they actually sold for. So even with the milling it still looks like about $300 to upgrade your heads going this route. Seems like a great bang for the buck mod IMO. I like it !
Like others have said I don't think you will pick up that great of gains with just slapping on these heads. I would say at a bare minimum you would need to get headers to see any real gains. With these heads you would be taking in quite a bit more air but it would be choked by the stock manifolds.
I would be very interested to see what these heads with headers would lay down. I would guess in the 385 to 390 hp range. I don't think there's been a single person to put these heads on without a cam but hey, someones got to be the first to do it.
Like others have said I don't think you will pick up that great of gains with just slapping on these heads. I would say at a bare minimum you would need to get headers to see any real gains. With these heads you would be taking in quite a bit more air but it would be choked by the stock manifolds.
I would be very interested to see what these heads with headers would lay down. I would guess in the 385 to 390 hp range. I don't think there's been a single person to put these heads on without a cam but hey, someones got to be the first to do it.
I'd think with some LTs, OTR, ported intake or FAST you could see 400 WHP on a M6. I find this very attractive since I wouldnt have to worry about driveability with a cam, wouldnt have to add the expense of a stall + install plus tune etc.
I am very tempted to go this route , LTs and L92 heads with the added flow my rockers are giving me I think it would be a pretty mean machine with virtually stock driveability Hell could get LTs and heads for less then 1K
Dont get me wrong, the L92/LS3 heads are good, maybe even great. However, they are not the end all be all heads! If you are gonna stay stock cubes with cam/heads, or even a mild stroker then they are prolly ok. But for BIG numbers, or BIG pressure(boost) applications they are barely better than stock. When i say barely better i mean as far as a longevity/durability/strength standpoint, where the stock 243's would lift, lose gaskets or push water so will the L92's. Im not knocking them, i have just seen these heads recommended for applications where an aftermarket set with thicker decks is neccessary.
For the applications in this thread they are fine, and would prolly be a decent bang for the buck mod, but it will HAVE TO be mated with a different cam to gain any decent power IMO since the LS3 has the advantage of more cubes and a slightly bigger cam when you exclude the heads from the picture.
Dont get me wrong, the L92/LS3 heads are good, maybe even great. However, they are not the end all be all heads! If you are gonna stay stock cubes with cam/heads, or even a mild stroker then they are prolly ok. But for BIG numbers, or BIG pressure(boost) applications they are barely better than stock. When i say barely better i mean as far as a longevity/durability/strength standpoint, where the stock 243's would lift, lose gaskets or push water so will the L92's. Im not knocking them, i have just seen these heads recommended for applications where an aftermarket set with thicker decks is neccessary.
For the applications in this thread they are fine, and would prolly be a decent bang for the buck mod, but it will HAVE TO be mated with a different cam to gain any decent power IMO since the LS3 has the advantage of more cubes and a slightly bigger cam when you exclude the heads from the picture.
Well it looks like this might not be such a good idea then. I was talking to a few friends with LS2 and LS3 vettes and getting there feedback and it doesnt look like it would be worth it to do this mode without a cam.
I was hoping to gain 15-20 to the wheels after a head swap to an LS3 but I'm basically told I'm not gonna see these results. I was also thinking maybe with an LS3 intake ported I might see an extra 5-10 to the wheels.
I wanna do this so bad cause it seems like a pretty decent sleeper setup but if it doesnt yield the results there is no point.
My buddy is betting me if I was to do this setup I would be really lucky to break 400 to the tires!! he says Maybe with an M6. That really pisses on my parade.
LS3 heads milled with bigger valves, ported LS3 intake and full bolt-ons!?!? WTF I've seen bolt on GTO's come close with full bolt-ons to 400 to the wheels. Yeah I know they're M6's.
I'd think with some LTs, OTR, ported intake or FAST you could see 400 WHP on a M6. I find this very attractive since I wouldnt have to worry about driveability with a cam, wouldnt have to add the expense of a stall + install plus tune etc.
I am very tempted to go this route , LTs and L92 heads with the added flow my rockers are giving me I think it would be a pretty mean machine with virtually stock driveability Hell could get LTs and heads for less then 1K
I am thinking the same thing you are.... Drivability is huge to me. I just dont see it worth it anymore if I wont break in to the low 400s. I can totally see this project costing me a $1000 bucks after all said and done.
2006 GTO Owner
Hell could get LTs and heads for less then 1K 
