YELLOHHH

I plan to do heads and cam in the spring. I just want to know the difference between the two. Would a fully ported LS1 be as good as a fully ported LS6? I was thinking I would go with the LS6, but if there is no difference, than what's the point?

Greg
:cool:

AnteVenom

Try to track down C5PIG. He has LS6 heads in his head/cam package meanwhile I have LS1 Stage II heads.

C5PIG Dynoed at 429RWHP - I Dynoed at 418 RWHP. Both have same tuner, CARTEK.

Good Luck :cheers: :smash: :smash:

MattG

If you are going to go with a REAL agressive camshaft I think the difference may be about 5-7rwhp from ported LS6 heads to ported LS1 heads. Mind you this 5-7 rwhp would probably cost you $1400 for the new LS6 castings.

Ported LS6 heads really only shine in performance at higher lifts, meaning you have to go with a pretty big cam to truly take advantage of them.

On a stroker motor, I think the LS6 heads are more of an advantage and probably more worth the money.

davidfarmer

They actually raised the port roof on the LS6 heads, so the LS6 is definitely better when all is said and done. However, ported LS1's will flow as good as stock LS6's, if not better.

I have some LS6 heads (brand new assembled) and an 01' Z06 cam if anyone is interested. I need $1400 for the heads, $1500 for the heads and cam, or you can get heads, cam, intake, injectors (LS6), and LS6 throttel body for $1900.

Dave

Shinobi'sZ

I agree with MattG and disagree with the other statement about Ported LS1 heads only being equal to stock LS6 heads. If you want to know the differences you have to look at the flow numbers. The numbers I have looked at show that when heads (LS6, LS1) are aggressively ported the difference is between 5-7 horsepower above 6000 RPM's. So the real deal is that if you have LS6 it is a no brainer to have them as a core for exchange with LS6 Ported Heads, if you have LS1 heads, you have to make the decision as to whether or not you feel $1400 is worth 5-7 horsepower above 6000 RPM. My information comes from both Jayson @ MTI and Nick, MattG & Ralph Gobel...ARE. The highest yield is when using a stroker, oh yeah and Dave from Cartek told me the same thing. Cartek and Katech had some good LS1 for LS6 exchanges. I investigated this fully before I floated the bill for my heads and cam setup. Good Luck. :cool:

Ram Air Tony

generally between 5 and 10 rwhp from what I have seen on this forum

hope that helps

Chris@SD

With the raised runner design of the LS6 heads, you might only get 5-7 peak HP(concervative) but you will also gain HP throughout the curve. As I have said 100 times before, peak HP numbers are good for nothing but braging rights. I will take a fat curve that is down on peak any day of the week and I guarantee that i am waiting for you 1320 feet later. :)

JMHO,

Shinobi'sZ

Honestly I would have like to have got the LS6 heads but it was the fact I had to buy the LS6 castings. It just was not economically viable for me to do so....to pay $1400.00 for the at a max 5-10 horsepower. Hey now though wait a minute, does that ARE Vette, SW, or that F Body running in the 9's have LS6 heads? :D

Garceeya

I agree with all from above. Not worth $1400 difference for castings. I have stage II GTP's and got the numbers in the sig below.

STAGED

About 12-15 flywheel hp on ported LS6s vs. "equally ported" LS1s. That's 1.5 mph trap speed or a way to allow one to run a milder cam to achieve a horsepower target. Take $1500 for LS6 castings, subtract $600 for selling your assembled LS1 stock heads and for $900 you get a chance to run a reasonably smooth cam and still bust 120mph traps thru cats as opposed to running a slightly lumpier cam to do the same. And these heads will reap more benefits down the road with boost and/or more cubes. I also think port velocity for given cubes and rpm are higher in the LS6 (a big goal in OEM development of heads) which contributes to a broad fat powerband.

kewlbrz

You can get bare, brand new GM LS6 castings pn# 12560801 for around $1350 bucks pair.

Also you can get LS1 heads all day long on ebay for 250 - 300 bucks a pair.

Also, aside from LS1 LS6 castings. I know some like black-ht (chris) are running the ported 5.3 aluminum truck heads. These heads have a smaller combustion chamber and im hearing the characteristics of the chamber design are better for performance.




[Modified by kewlbrz, 10:18 AM 10/25/2001]

YELLOHHH

ttt keep the info coming.


Greg
:cool:

C5_PIG

When I had the LS1 heads with cam my car was dynoing at 390 then 409 after the LS6 manifold was put on. Then after the LS6 with a little more aggressive cam 113 lobe sepration vs 114, the car dynoed at 427RWHP. I know this is all that bench racing crap, but my car ran an 11.9@117 with the LS1 heads. With the LS6 heads the car ran an 11.64@121. I couldn't duplicate this due to the fact E-Town scolded me after I ran 11.8's back to back. So they were not happy with me when I ran faster. I just wish I could have run some more so I could have praticed my 60', which I ran an 1.9 when I ran the 11.6. Anyway, Julio at Cartek is going to tweak my computer and some other little tricks, expects to get round 440rwhp with the LS6 heads and have my car run low 11's with better suspension setup. BTW I 've seen Cartek get 419RWHP out of LS1 heads and cam car and that car was running 11.7's, convertible too. I will keep you posted as I'm sure I have not seen the full potential of these LS6 heads. Darth Vetter(a Z06 with heads and cam) is also another car you should check out. I got these heads just incase I do a stroker down the road, then they will really shine.

hpcubed

Ok, I have basically the same car as C5-Pig but I have the ported LS1 heads. The difference I see is in the torque numbers. My car made 427.9 RWHP but only 385 RWTQ. C5-PIG are you running through the cats? Cuz you pick up some torque without cats.

..................
99HT
MMS
427.9 RWHP
385 RWTQ

ScreaminDemon

ARE just did a fully ported LS1 vs fully ported LS6 head comparison along with the intake and exhaust manifolds in an issue of GM High Tech Performance earlier this year. It stated that they only got 7 to 9 more hp from the LS6 heads, not worth the price difference at this time. I left the issue at work, but I can get you the month of issue if you want it. I would go with LS6 intake and exhausts with LS1 stageII heads to match.. :seeya


[Modified by ScreaminDemon, 3:30 PM 10/26/2001]

C5_PIG

Hpcubed, yes I am still running through the stock cats.

cendres

Here is the story, it is from the May 2001 issue of GMHTP.

Head North, Young Man!
Ported LS6 heads and manifold help us squeeze 435 rwhp from our Z28
Text and photos by Chris Endres

For nearly a year and a half, LS1 devotees had been salivating at the mere notion of the evolutionary LS6 engine. To say it had been highly anticipated is no small understatement. Now that the new motor is finally here, some of the more rabid enthusiasts have been slobbering all over themselves seeking information on how the new motor really performs, and how it will respond to modification. Their curiosity is completely selfish of course, as they want to get a hold of the key components to add to their own rides. Naturally, we here at GMHTP are as guilty of this as anyone.

So, when we received a call from Nick Agostino inquiring if we’d be interested in testing a pair of Stage II ported LS6 cylinder heads and a LS6 intake manifold on our Z28 project car, we could barely contain ourselves. Moments later, after wiping the drool from our own chins, we had the car loaded up with notepads, laptops and a satchel full of photo equipment for the trip north to Agostino Racing Engines in Toronto.

For those that might not remember, ARE set us up with a killer ported head and cam package for our not-so-subtle silver Z28 last year. This is the combination that put our 3650-pound down the track in 11.69 seconds at 118mph in 80° weather way back in February 2000 (New Dog, Old Tricks; GMHTP May/July 2000). At that time, the car recorded a very stout final power reading of 406 hp and 392 lb.-ft of torque at the rear wheels. It is important to note that no other equipment changes were made to the car for the purpose of this new testing. The camshaft is the same ARE-spec (222/230° duration, .534/.544-inches of lift, 114° lobe separation angle) Lunati piece from the previous combination, as are all other components, including the Grotyohann long-tube headers, full exhaust (no cut-outs), stock injectors, ported mass-air flow sensor, and the ported stock throttle body. In other words, it was to be a straight up comparison.

Cylinder heads

That the LS6 heads outflow standard-issue LS1 heads has never been in question. Chevrolet tells us the new for 2001 LS6 as installed in a Z06 is good for 40 horsepower above and beyond the 345 ponies found in a typical LS1-powered Corvette. ARE’s airflow testing backs up this number as accurate, if not a bit conservative. The difference between the LS1 and LS6 cylinder heads is substantial when comparing stock unmodified units. The LS6 is clearly superior here, out-flowing the LS1 heads by more than 30cfm at .500-inch lift. But that’s stock and unmodified heads. We were determined to compare our pair of ported LS1 heads directly to a similarly prepared pair of ported LS6 pieces.

Many people believe the extra horsepower found in the LS6 mill to be mostly in the cylinder heads, but we weren’t so sure. Several components contribute to the additional power output: the cylinder heads, intake manifold and certainly the camshaft. Of particular interest to most enthusiasts are the heads and intake.

“We found it interesting,” explains Agostino, “that when the heads are ported, the margin in airflow between them closes significantly. Specifically, airflow is within 10-cfm throughout the tested range.” Take a look at the flow chart in the sidebar Go With the Flow! If you study it carefully, you will see that the ported LS1 heads actually out-flow the ported LS6 heads by a small margin until .350-inch valve lift. From there on, the LS6 has the edge, but it is a narrow one.

Flow numbers are informative, but they are only part of the picture. The question remains: How will the LS6 ported heads perform on a stock short-block LS1? To find out, Agostino and crew ported our new LS6 heads in a fashion consistent with original LS1 pieces we tested last year. They then treated the new heads to the same size Manley stainless steel valves (2.055 intake /1.60 exhaust), Comp springs and titanium retainers. Once prepared, the heads were swapped onto the Camaro and teamed with the original LS1 manifold. The LS6 cylinder heads are a direct bolt-on, and completely interchangeable with our original LS1’s. A quick drive around town with a few WOT punches proved somewhat disappointing. Either our butt-o-meter was out of calibration, or the heads didn’t provide much gain over the old LS1 parts. A trip to the dyno validated our initial impression: We gained just over 9 horsepower and 7 lb.-ft. of torque.

Even though the power numbers aren’t what we had hoped for, LS6 cylinder heads are not without their merits. “They would probably be most beneficial on an engine that will see use of a power adder,” Agostino tells us, “such as nitrous or turbocharging. Though cast from the same 356-T6 aluminum as the LS1 heads, the LS6 heads are a bit heavier and appear to have a bit more beef to their deck surface. This will help the head retain its shape under high cylinder pressures, and in turn, make it less likely to blow head gaskets. The combustion chamber is slightly more efficient, which will shorten burn times. This ultimately means less ignition timing will be required to produce the same power as an LS1 head. And because less timing is more efficient, the heads will allow the engine to produce more torque,” he concludes.

Some may argue that since you can pick up a solid 35-cfm with a pair of stock LS6 heads over the stock LS1 heads, that they may be a cost-effective alternative to costly porting of the stock pieces. While it sounds good in theory, the reality is that LS6 castings are very rare and therefore very expensive right now. Hopefully this will moderate as more parts show up in the system, but for now, porting the LS1 heads seem to be the way to go. Yes, top quality porting is expensive, but so are LS6 castings. And in the end, the stock LS6’s flow numbers and power production will not hold a candle to a pair of pro-ported LS1 heads.


Manifold

We told you last year that the stock LS1 manifold is a competent performer, and we stand by that statement. When used in light bolt-on applications, it is more than adequate. But when the engine is modified with an extremely efficient pair of cylinder heads and a camshaft matched to take advantage of that efficiency, things change.

After our disappointment with the heads, we were hoping for good things to happen once we bolted on the LS6 manifold. It, too, is pretty much a direct bolt-on, but does require a few simple changes to be made. The manifold has no EGR provision, and since we don’t have to contend with the smog *****, we opted to eliminate the EGR from our car completely. We simply fabricated a small block-off plate for the passenger side header fitting and removed the EGR valve from the car. All EGR functions have been eliminated in the PCM (more on this later), so it is not throwing codes. For those that wish to retain EGR functionality, Agostino Racing is also able to modify the manifold to accept the EGR feed.

The under-manifold coolant lines will need to be re-routed, as there is precious little room under the manifold because of its increased plenum volume. We did this simply and cheaply by using some rubber fuel line. You would be well-advised to opt to replace the coolant lines with those from an ’01 LS1 F-body. This is definitely the right way to do it, but at the time we did the swap, they were not yet available in the GM parts system. They’ll swap right on, and should be readily available by the time you read this.

Once these tasks were completed, it was time to take the car for another test blast. Holy smokes, did it ever come to life! Suddenly we had all of the power gain we had been hoping for, and then some. We couldn’t wait to get the car back on the dyno. Once there, we were very happy to learn that the car had picked up an additional 20 horsepower and 16 ft.-lbs. of torque, bringing our total gain for the LS6 components to 29 and 23, respectively! Clearly, the intake manifold was a bottleneck in our combination.

“Testing on a variety of aggressive LS1 head and cam equipped cars has consistently shown the LS6 manifold to be worth between 10- and 20-rwhp,” says Agostino. There may be those among you that will make the assumption that an LS6 intake is automatically worth 20 horsepower just by bolting it up. We hate to be the bearer of bad news, but we’re here to tell you this is just not the case. The truth of the matter is that the manifold was worth 20 horsepower on our already very deep-breathing motor. With the motor in stock form, there is very little benefit to going to an LS6 intake. Until such time as the LS1 intake becomes a bottleneck, there is nothing to be gained by replacing it with a more efficient piece. The upshot is this: Don't expect big (or any) gains with an LS6 intake unless you've installed a very efficient pair of cylinder heads first. You'll likely be disappointed with the gains otherwise.

Tuning and Driving Impressions

We turned to Superchips for PCM calibration issues associated with this project. They were able to disable all EGR functions which allowed us to run free of Service Engine Soon lights, while leaving the remaining operating parameters untouched. We found the car running rather lean through the mid-range rpms while dyno-testing. One call to Superchips was all it took to get our fuel map adjusted accordingly and back where it should be. In fact, we tried adjusting on our faithful MAF Translator and gained virtually nothing. That tells us the tuning is pretty much spot-on.

Superchips has partnered with selected shops that use their Microtuner 2001 box to eliminate the need to ship the PCM around the continent for custom tuning.. The way it works is this: The shop fills out a form asking for all pertinent information about a car’s combination. They fax the info to Superchips who then gets right to work on the calibration. When complete, the calibration file is placed on the company’s ftp site from which, the shop can download it to the Microtuner box. From there it is a simple five-minute procedure to load the program into the car’s PCM. We like the fact that the car does not become a 3500-pound paperweight while the PCM is en route to and from the programmer. Turn-around times are drastically reduced, as well. We never waited for more than a day or so for our new programs!

Driving the car takes more self-restraint than ever. Throttle response is immediate and authoritative. Aggressive throttle usage in any of the first three gears amounts to massive fishtailing and drastically reduced tire life. All in all, it’s a great deal of fun, but we can envision this being detrimental to our insurance rates in short order!

What To Do?

So, are the LS6 top end components a good investment? Well, as with most things, the answer is a resounding “It depends”. The LS6 heads picked up just 9 horsepower and 7 ft-lbs. of torque when paired with the stock LS1 manifold. The bang for the buck just doesn’t seem to be there with the cylinder heads, at least when used on a stock displacement power plant and LS1 manifold. The heads appear to be best suited for those building an all-out, big-cube, maximum-effort engine. Unless you already have a pair of LS6 heads, or really want to have the bragging rights, we suggest you pass on the LS6 heads for now.

Swapping on an LS6 manifold brought our gain to 30 horsepower and 23 ft.-lbs. of torque with this combination. Torque and horsepower are up everywhere, not just the peak numbers. If your engine is modified to the point at which the ‘97-’00 LS1 manifold has become a restriction, the LS6 piece is the ticket. What makes it even better is the fact that the manifold is affordable, and is about to become readily available through GM Performance Parts.

Flow testing has shown the biggest gains per dollar spent are found with a pair of ported LS1 heads combined with an LS6 manifold. “We are able to prepare the head a bit more aggressively when we know that a LS6 manifold is to be used,” Agostino told us. “As the flow data shows, they end up being very similar to a ported LS6 head, and actually outflow the LS6’s at low lift.”

You really can’t go wrong with either combination of ported LS1 or LS6 heads when teamed with the LS6 manifold. The next question is how they will perform when bolted to a big-bore stroker. We’ll keep you posted…



Sidebar: Go With the Flow!

Agostino Racing Engines has done extensive airflow testing on every conceivable combination of stock and ported cylinder heads, separately and with manifolds. The tests provided some expected and some unexpected results.

Of particular note is the fact that the ported LS1 head / LS6 manifold out-flow the ported LS6 / LS6 combination until valve lift reaches .450-inches. At that point, the LS6 / LS6 combination overcomes, but think about it: When open, where does the valve spend most of its time? If you said at lower lift, you are on the right track.

Also worth noting is the big airflow gain shown by the 6-liter truck manifold over the LS1 piece, especially at low valve lift. Again, the margin narrows at higher lift. One other important note about the truck manifold: It won’t fit beneath the F-body’s cowl without modification, so don’t bother knocking yourself out trying to find one.

We believe the airflow numbers validate our opinion of the ported LS1 heads and LS6 manifold as the best bang for the buck. What do you think?

Cylinder Head Intake Manifold .200” .300” .350” .400” .450” .500” .550” .600”
Stock LS1 N/A 137 187 207 223 228 237 242 243
Stock LS6 N/A 156 204 225 243 257 268 275 278
Ported LS1* N/A 144 200 225 245 261 272 283 292
Ported LS1** N/A 164 217 234 253 270 284 296 305
Ported LS6 N/A 159 212 236 255 272 300 307 314
Stock LS1 LS1 136 184 200 214 222 227 229 235
Stock LS1 LS6 136 186 206 223 227 236 241 242
Stock LS6 LS1 156 199 212 224 232 238 243 247
Stock LS6 LS6 154 204 220 235 247 257 263 265

Ported LS1** LS1 141 185 205 222 232 241 251 258
Ported LS1** Truck 163 206 224 237 249 262 265 270
Ported LS1** LS6 166 211 229 244 257 269 277 283
Ported LS6 LS1 156 199 217 230 242 253 263 268
Ported LS6 LS6 153 202 222 241 257 270 280 289
* New Dog, Old Tricks; GMHTP May/July 2000
** Latest revision.

Cylinder Head Intake Manifold Horsepower Torque
Ported LS1 LS1 406 393
Ported LS1 LS6* 423 405
Ported LS6 LS1 413 400
Ported LS6 LS6 435 416
*alternate test car, set up identically

0Sales@MVPAutoParts.com

Garceeya,

If you don't mind, may I ask how much did you pay for the GTP stage II heads?

Have you ran into any problems running GTP stage II heads with MTI T1 cam? I am scheduled to have MTI T1 installed on 11/20. I plan on getting heads few month down the road after that but don't think I can afford MTI stage II @ $2800, so I am looking for heads from other vendors :D

Thanks
-Tuan

ScreaminDemon

Jez, did you actually type all that after I mentioned the article? :eek:

cendres

No, I sure didn't. i just copied and pasted my original Word file. That would also be the reason for any slight differences from the article you saw; this version was unedited... :cheers:

Chris