There seems to be a lot more info on the LS7 coming out, finally. The latest dynos being pushed to the spotlight has me wondering a few things.

First, i'd like to compile the current known information to confirm that it is correct.

Heads:
12* valve angle (non canted)
263cc or 283cc intake ports (seen both, true value?)
2.2/1.61 valves
Flow #s: http://www.gearchatter.com/viewtopic11202.php
Offset rocker arms are used to eliminate the pushrod pinch area

Cam specs:
211/230 @ .050
.591" lift on both sides
114 LSA (forgot where i saw this, probably off the mark)

As for the dyno, LGM seems to have the jump start on this:
http://forums.corvetteforum.com/show...1&forum_id=100
(There are a couple more dynos from LGM that are very close to this)
Stock in the 440s, 470-480s with headers. Speculation from LGM is with the addition of a CAI and tune, when the software becomes available, it will be very close to 500rwhp maybe a touch more. On to other things....

Looking at the short side radius: http://popularhotrodding.com/tech/0504phr_ls7_15_z.jpg .... why is it so sharp? How would that sharp of a radius impact ram tuning? Does the C5R head have a similar design?

The LS7 and SB2.2 look frightenly similar too. LS7 chambers: http://corvettefever.com/techarticle...04_ls7_5_z.jpg . Comparing that to pictures of SB2.2 chambers i have on my CPU, they are almost exact copies of eachother (LS7 being a little more shallow). Even pictures of the entire heads leave me with a sense that GM had SB2.2 blueprints somewhere on the table when designing the LS7.

Anyone care to guess what this engine will do with a more aggressive cam? What about a complete top end package? Could we dare say 700hp on pump gas being possible?

 

excuse me for my ignorance but what is a SB2.2

 

Think NASCAR.

 

what better to put in your daily driver...

give me a cobalt and a solstice with one of these 427's...

 

Those are some awesome numbers. Hard to believe it gained approximately 100 ft/lbs. at 2500 RPM's with LG's headers!!!

 

Lou’s local and we are both in the same car club. He’s really cleaned up his act from what it used to be but you still have to be a bit cautious regarding his dyno numbers. His dyno reads just like everyone else but he’s been known to remove belts, position the car just right on the dyno and even remove the rear brakes to get better numbers. Removing the rear brakes picks up about 10 hp on the dyno.

Regardless……………… I’m terribly impressed with the Z06 and got one on my shopping list. Maybe next year as I’ve learned the hard way to not buy the first year of anything.

I’ll let someone else with more guts (maybe also more money) get all the glory and I’ll also let them sort out the bugs.

 

...and pay the $20K "dealer premium" ?

Had to chuckle at the "cleaned up his act.."

 

You should have heard all the stuff going on 6-7 years ago about LGM and you'd have a better idea of what I'm talking about.

Bought a brand new 97 SS and with 200 miles on it, took it to Lou's shop and paid almost $1,000.00 for the best magic beans money could buy. All the hot stuff like power programmer, LE1 smooth bellows, throttle body widget, air filter, 160 thermo, skip shift eliminator, etc. Had a turbo Supra and a twin turbo VR4 just prior and bolt on’s worked well on both cars, so I bit the hook.

Was told I’d pick up 30-35 hp (keep in mind he had his own dyno back then) and when I dynoed the car at another shop……….. lost 3 hp. Needless to say I’m not on the best of terms with Lou but to his credit, I’ve seen him get better.

Still don’t trust his before and after power gains with just headers. Think his headers are pretty good and I’m sure there is some there, it’s just how much is the question.

 

Mainly just talking about the down low numbers. Can you elevate them and NOT the rest of the graph??

 

I suppose you could fool the muffler bypass by opening it early. I think WOT plus 3500 rpm are the stock minimum to get them open. There idea is less restriction and more sound but without failing the drive-by noise requirements. Anyhow, one could fairly easily change the computers mind and open them whenever WOT was reached.

Not saying this was done when headers were installed, but it could be done, and it might show some help at the low end.

I don't think the stock headers are tuned for low end torque. It's tough enough getting the stock torque to the ground in first gear. I suggest the low end of the stock torque curve makes it easy to launch and clip off sub 4 second 0-60, since no shift is required. I do want to drive one and see for myself.

My $.02

 

Most likely, but there's little point in doing that. I'm sure smaller intake/head runners
might improve lower RPM efficiency, but it would limit overall performance
I would think.

Fast Caddie,

I see what you're saying. I always thought a 'line of sight' design to the valve would have an advantage.

 

Yea that's what caught my attention. From my short stint in learning about cylinder heads (on here and from Vizard's books), it seems that the shortside radius is critical since without a smooth transition, the lower part of the air stream can "overshoot" the valve area.... causing a lot of turbulance and distrupt flow when entering through the valve curtain area. But i'm FAR from being an expert, so i figured it's best to ask about it here. Not trying to dis it or anything about the matter, i genuinely want to know why it may be the way it is and possible what the effects on torque production are. That and just how good these heads are, since GM likes to allude to them as being as close to a "race" head as an OEM gets.

 

I remember those days as well as the track rental he had at Ennis where the fastest LT1 car he had running out there was blown and in the mid to high 12's...

 

Something else I recall reading about the head design is the quench area.

"double quench"?
The pads are designed to push charge to the middle of the chamber, as opposed to one side?

I believe the LS7 uses a multi-layer head gasket which is fairly thick in comparison
to the LS6.

Any bets that the piston crown sits higher in the bore to compensate?

Last observation looking at the chamber pic:

Does that spark plug sit closer to the center than most designs? Does this
help focus more pressure over the center of the piston during combustion?

 

Yes, "the good ol days."

If my memory serves me correct he rented Ennis, made a big whoop about it and only ran one lane because of the cost of insurance. That was fun to watch single passes! Slow single passes at that. Think I stuck around for about 15 minutes.

Again, I honestly think his new headers are pretty good and they are more than just headers as it goes all the way back to the mufflers. But, how much do you gain from them?

It's still Lou, bless his heart; he still can't quite resist the temptation.