hell yea they do. AFR is gonna have to scramble to copy this casting, and QUICK. I don't know how much they will be able to do with it, since its going to be C5R based already. Maybe just add the AFR touch to it like the thicker deck and a bit more p2v clearance. who knows.

 

I think AFR already has a set of BIG port heads on the drawing board. It was mentioned a while back in another post. Now, I have no idea if that is true or not just something I saw mentioned. AFR 245's

 

PHR said the factory flow #s showed 360 on the cold side and 280+ on the hot side @ 28" of H2O and I think only .600 lift. Basically if you look @ the ports, it's the old c5r heads, which they based off the SB2 NASCAR Cup head. How long before someone goes to a splayed valve head now to out flow the LS7 heads? Gotta love the BB intake vavles in a small block, that is just insane. Pick up the lastest issue of Popular Hot Roding to get the full scope, good article on this mill there. I think Hot Rod (sister publication) will be doing the same as well.

 

Guys...

Total speculation here, but my guess is the LS7 heads will be stupid expensive. Look at what GM is charging for a C5R block...When ANY of the aftermarket suppliers come out with an aluminum LS big bore block, watch the price of the C5R blocks drop like a bad stock pick.

Don't get me wrong, Im psyched GM is coming out with an architecture that we can ultimately get our hands on and hopefully improve on it as well, but till the aftermarket starts making parts for that head (unlikely for a while....too rare), I think GM will be charging an arm and a leg for the intake, rockers, castings, etc. to make the conversion a reality.

I view this head set-up like taking a conventional BBC headed motor and stepping up to a Big Chief/Pro-Stock style set-up....usually VERY expensive when the smoke clears, but the good news is that is does bring a new level of power to the table....something that simply couldn't have been reached with a more conventional "bolt-on" style cylinder head.

Its great that things are in the works, but personally, I think it will be awhile till its a viable option for the average Joe....unless Joe just pulled a bank job....LOL

JMHO....

Tony M.

 

Tony, does this mean you're working on some affordable c5r style heads?

 

The C5R block is a race item, and it is unlikely that it is produced in any kind of a cost effective manner. Hence the $6K+ price tag. The LS7 heads are going on a relatively large number of engines, so GM's cost of manufacture should be closer to reasonable.

In any case, I hope that the above is correct; my 427 needs a set badly.

 

I bet there less than 3K complete....
Productions heads,Productions block hence no high dollar C5R type price tag...

2006 is going to be awesome..
650RWHP 427 to 447 LS2 based setups wil be common

 

But will they work with a 4" bore on an LS2?

 

After reading more about these heads and looking at the pictures in the new Corvette Fever magazine I doubt they will be less than $3K (though I hope so). The writer actually had a chance to examine production heads. The LS7 heads are a work of art and according to the article unofficial flow numbers are 360 cfm on the intake and 214 on the exhaust at .591 lift flowed at 28" of water.

To quote the article "Those ports are the work of a master craftsman with a grasp of the nuances of airflow and port shape that made it clear these cylinder heads are truly something special." The heads were a collaboration between GM and Mike Chapman.

Here are some bullet points from the 10 page article:

* 2.20 ti intake valve longer than previous Gen III/IV valves
* 1.61 exhaust vavle (sodium filled) longer than previous Gen III/IV valves
* 12 degree valve angle
* raised intake runner
* Offset intake rocker arm to provide increase port width
* CNC machined combustion chamber
* pressed-in dry cylinder liners
* Forged main caps are installed and torqued during machining operations. Truer tolerances result from this due to the stressed block during machining.
* Forged 4140 chrome-moly steel crankshaft
*friction-reducing coating on pistion skirt.
*All engines are rigorously inspected and hot-tested in a 20 minute run cycle upon completion.

The last point listed above and another quote from the site manager of the Performance Build Center Timothy Scag: "It was important to step away from ther high-volume world we all had lived for so long and soak in the cadence of these specialized environments." lead me to believe an LS7 crate motor and it's separate parts will be very spendy for us average working people.

 

My bets is these go to about 430CFM with porting. 350CFM is probably
seen by @.5" lift and 300CFM by .4" lift.

These larger strokers are going to be making some serious power, even with
hydro cams. Solid rollers are going to be going to 800-900HP with
the right supporting hardware and enough compression.

My bets is they are not compatible with a 4" bore, that you must run the 4.1"
or greater on the bore.

Chevy did right

 

I don't know how much is going to be left on the table with the LS7 heads, since they will be CNC'd out of the box. I'm not saying that they will be perfect and that there won't be some possible improvements, but I think that the difference between an out-of-the-box LS7 head and a thoroughly worked unit will be smaller (percentage-wise) than the other LSx castings.

Sure, those big flow numbers may be possible on C5R heads, but those heads were intentionally designed with THICK port walls so they could be really heavily massaged... I'd be pretty surprised if the LS7 heads had that much meat around the ports.

 

Burnout, I made the assumption as you saw that these could go to about
where the C5R's could.

GM was smart with the Ti only on the intake side.

My thought was that even though they are CNC'd for consistency
and accuracy that the 2.2" intake valve indicates that they can support
alot more port ( we hope that the meat is there ).

We will find out later.

If the verdict is these can only go to 390CFM with porting, no one will
be complaining.

The mid lift flows must be excellent with the large 2.2" valve and raised
port. I wonder where it hits the 300CFM by..

 

I'm waiting for the 7.0 block...
Then will see what the parts will cost...

I figure a 4.1 bore with a short stroke will be **** with these heads.
Big Bore 375CI and heads that will go to 8000rpm

Serious power with a LSX/90 and the right cam....I'd need better rods/pistons and few other odds/ends but other than that its easy..I think 1.5RWHP per cube is attainable so figure a little engine like this COULD make 570RWHP,imaging a 447CI making 670RW to 700RW with these parts.

I do agree though its all speculation,This stuff maybe $$$$$$$$$$$$$
We'll see...

 

Considering it's report this motor is making Max HP about 300~400 RPM short of factory Redline would lead you to believe that it's flowing earlier in the revs and it would also be a good assumption that it has the room to be more up top with the right cam to take advantage of it.

and on a side note, I miss quoted up top on the exhaust #s. Looked @ the article again and whoever posted the 210~214 numbers is right.

 

Big-DEN, I kind of figured that the C5R heads were the basis for your estimation. The thing that I have to keep reminding myself of is that the LS7 heads are based on the C5R casting, but are not the same. One of my other big questions right now is the deck thickness on the LS7 heads... we all know that other factory LSx castings can take some cylinder pressure, but not like the AFRs with their thick deck.

I am with you, the 2.20 intake is fricking IMPRESSIVE (though I have to admit that I am wondering about the (relatively) small exhaust valve), and we could very well see some damned nice flow numbers out of these heads... hopefully, with the (comparitively) big cylinders of the 427, port velocity will still be relatively high.

JS- I probably don't need to tell you this, but the FAST (I assume that's what you were referring to when you said "LSX") intake won't fit these heads... you'll be stuck with either the stock LS7 piece or some crazy aftermarket sheetmetal piece (unless you go for the $$$$$$$$$ Kinsler setup).

 

Time my friend, time. Look @ what happens when Gen III stuff has been out for almost 10 years and the cult aftermarket is finally starting to produce more pieces and grow the competition. Let us hope that production piece can be had from GMPP for reasonable amounts of money.

 

Opps I forgot...
Your right the LSX wont work w/that head....
Theres another part your going to need to buy to run these heads.

If the stuff is reasonable we'll all have it....
If not then only the rich guys will have all the fun

 

Big plenum sheetmetal intakes aren't exactly rocket science though. You just need to make sure that you can match up your runners properly to the ports.

 

Theres always been a runner length problems with the sheet metal intakes.
So that more power isnt made to a very high rpm.

A 3"-5" runner isn't going to resant tune until a seriously high RPM. But
a 9-12" runner will resonant tune where it is needed.

I always thought they could do something that looks like IR with a "BOX" over
it.

Like:

_______________________________
| |
_________________ |
_________________ |
| __________________|
| __________________
_________________ |
_________________ |
| __________________|
| __________________
_________________ |
_________________ |
| __________________|
| __________________
_________________ |
_________________ |
| __________________|
| __________________
|__________ ______________|
| |
______

 

sb427- while sheetmetal intakes aren't rocket science, they ARE frequently expensive (unless you have the skill to fab one yourself, which many of us do not).

Big-DEN- Accel used to make an intake like you're describing for the SBC called the Super Ram or something (was used with a TPI-style base):



Inside that plenum/box is a runner/air horn for each cylinder. I don't really know how well they worked, but they had some LONG runners (probably every bit of 13-15 inches)... the heads of the day didn't really flow that well, so something making big torque below 5500 or so RPM was the way to go.