I agree GM has it going on...but these engines also have VVT do they not?
Will it hit 450 whp
TECH Senior Member
Joined: Jun 2016
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From: Central Cal.
They do, and it does work.... most of the time. Keep in mind some things are made to keep the customer satisfied, and the others to keep the EPA satisfied. This and DOD are done to do both. Do WE think they are such great ideas? Weeeellll…. not usually….
TECH Fanatic
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For a street car the ls6 head will make more torque and carry out to 7-7200 no problem. GM got away with it on the trucks because of VVT. If you were spinning to 8k+ and it was a 50/50 car then I'd understand the argument for ls3 heads but for a budget stroker street car? No way.
For a street car the ls6 head will make more torque and carry out to 7-7200 no problem. GM got away with it on the trucks because of VVT. If you were spinning to 8k+ and it was a 50/50 car then I'd understand the argument for ls3 heads but for a budget stroker street car? No way.
Everything he has said indicates this isn't a street car
Someone needs to call GM and tell them what idiots they are, they're putting rectangle heads on 4" bore motors in the 14+ 2500 and 3500 trucks. Man if someone would just tell them the valves are shrouded maybe they could get some low end out of those heavy duty trucks that are built for towing and moving around literal tons of weight.
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Verdad Gallardo I wasn't sure when they started but I knew they had been at it for a while, I just threw out a number, and I agree that they do very well.
And these aren't in light trucks, these are trucks that weigh around 7k and up that obviously produce plenty of low end and only on a 4" bore..
But can't run LS3 heads on a car that weighs less than half of those trucks or you'll lose too much low end, L O L
Sure, you may give up a couple of ft lbs on the low end, but I'm willing to bet the OP's car is going to have at least a 4k stall. The other part that's laughable is people recommending spending approx 3k more (high end cathedrals, big intake and TB) than a stock LS3 top end to make a couple of ft lbs more down low.. where your converter flashes right past
And these aren't in light trucks, these are trucks that weigh around 7k and up that obviously produce plenty of low end and only on a 4" bore..
But can't run LS3 heads on a car that weighs less than half of those trucks or you'll lose too much low end, L O L
Sure, you may give up a couple of ft lbs on the low end, but I'm willing to bet the OP's car is going to have at least a 4k stall. The other part that's laughable is people recommending spending approx 3k more (high end cathedrals, big intake and TB) than a stock LS3 top end to make a couple of ft lbs more down low.. where your converter flashes right past
For a street car the ls6 head will make more torque and carry out to 7-7200 no problem. GM got away with it on the trucks because of VVT. If you were spinning to 8k+ and it was a 50/50 car then I'd understand the argument for ls3 heads but for a budget stroker street car? No way.
10 Second Club
Joined: May 2009
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From: over dere
More torque where? All the dyno sheets I see show slight edge to cathedral ports under 3,500 rpm above that the LS3's take over...… Nobody I know that has a performance car/truck really gives a **** about losing a little torque down low if they gain from 3,500 to 7,000-8,000. We aren't talking tow trucks here lol
Brett at Land Speed Cylinder Heads explained thinking about making good power in this general way and keeping good drive ability.
- Smaller CC port cylinder heads respond well to big cams
- Big CC port heads can work well with smaller cams
What I've seen in real life and online supports that idea.
For instance a fat port GMPP head with 250 cc runners can and have made 400+ whp with a dinky little GT2-3 cam with 207/220 .570/.578 lift 118 and drive very well.
Stock ~200 cc runner heads can also make 400+ whp with a fat cam like a MS3 /MS4 ~ . 239/242, .649"/.600", 111.5 LSA, 110 ICL. Not as drive ability friendly but makes power.
So a big cam & big runner can really make some high rpm power if the intake can flow the air and bottom end take the high rpm.
Last edited by 99 Black Bird T/A; Nov 10, 2018 at 10:48 AM.
I'm always up for learning more about cylinder heads. Please spell it out for me.
FWIW - Velocity is important, wouldn't argue otherwise. There are a lot of factors. LS3 heads are well proven. It's even possible to increase the flow in an LS3 cylinder head by reconfiguring the intake port with epoxy and selective porting to flow 375+cfm with a ~245 cc volume intake runner. Makes outstanding hp. It's also expensive.
On The Tree
Joined: Aug 2007
Posts: 141
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The biggest difference between the 317 cathedral-port heads and the LS3 heads was the port shape and attending flow rates. The 317 offered peak intake flow numbers of 244 cfm, but the LS3 head peaked at a whopping 318 cfm! The LS3 head offered an additional 70 cfm over the stock 317 head!
So a ported stage 2 243 will flow 318 cfm also, maybe more, There would technically be no difference from the 243s to the lS3 except the 243s will have more street friendly TQ under 4000. Now you will all say you will port your LS3 heads and beat the ported 243s, well by the time you do all that just buy some AFRs or Trickflows and beat them all. Plus heads are not going to make your car unbeatable at the track, there are alot more pieces to the puzzle to make a fast car. Last time I checked nobody races CFM numbers or Dyno's.. This is a dumb debate, I bet there are a ton of 243 cars out there that will destroy LS3 engine and vice-versa.. Only thing anyone can do is build it and take it to the track.. Hell, I had a PAW 383 stroker that cost a total of 2500$ in a street car all steel, street tire, registered 68 Camaro and was putting tubbed out big blocks on the trailer in Palmdale. So build it the way you want and go race it, it really doesn't matter anyway due to the fact a LS2 cant compete with modern engines anymore anyways.
5.0 mustangs run 9s all day long with just a Blower and Tune, Hellcats run 9s, CTSv runs 9s and they all can be driven everyday in comfort..
So a ported stage 2 243 will flow 318 cfm also, maybe more, There would technically be no difference from the 243s to the lS3 except the 243s will have more street friendly TQ under 4000. Now you will all say you will port your LS3 heads and beat the ported 243s, well by the time you do all that just buy some AFRs or Trickflows and beat them all. Plus heads are not going to make your car unbeatable at the track, there are alot more pieces to the puzzle to make a fast car. Last time I checked nobody races CFM numbers or Dyno's.. This is a dumb debate, I bet there are a ton of 243 cars out there that will destroy LS3 engine and vice-versa.. Only thing anyone can do is build it and take it to the track.. Hell, I had a PAW 383 stroker that cost a total of 2500$ in a street car all steel, street tire, registered 68 Camaro and was putting tubbed out big blocks on the trailer in Palmdale. So build it the way you want and go race it, it really doesn't matter anyway due to the fact a LS2 cant compete with modern engines anymore anyways.
5.0 mustangs run 9s all day long with just a Blower and Tune, Hellcats run 9s, CTSv runs 9s and they all can be driven everyday in comfort..