Well, not really. Remember the LS7 has gobs of torque even at low rpm. Also, it only(!) has 325 mm section tires to put the torque down. With a overall ratio of about 9.0: 1 (3.42 final x 2.65 or so 1st gear for example), every 1000 rpm is less than 9 mph, and 7000 is about 61 mph.

I think launching a LS7 Z06 is going to be easy. If you've driven a C5 Z06 with about 75 lb-ft less peak torque, and certainly less at 2500, you'll see my point.

Corvette engineers have traditionally done a good job making the cars easy to drive. IMO, their biggest problem on the LS7/Z06 is keeping the launch from frying the tires. Bet they did it well again.

 

I was doing some reading this morning over on LS1tech about the LS7. I think the intake runners are going to be ~283cc, and flow in the upper 300's, maybe 400 with a great port job.

 

It was more like mid 300's.

EDIT: Just found this.

http://www.ls2gearchatter.com/test/LS7_Head_Flow.JPG

 

Yeah, mid 300's is what they're claiming.

The ports on these C5R heads are a tad longer (mid port length) than a sb2.2 and have plenty of volume. From what I've seen of sb2.2's I'm guessing it shouldn't be much of a stretch getting ~400 cfm out of the "R".

Going to make an excellent stroker motor head.

-Mindgame

 

No, these were pretty unmistakable. I have a picture of them back at the office and I'll try to get a scan tomorrow.

This particular configuration was just like the header shown in the article as it had 4 primaries joining at a "collector" at about the same primary length. Then the merge of pipes stayed seperate on through the collector. The collector looked like a huge 6" sewer pipe and you couldn't tell much about "how long" the primaries actually were.... where they converged etc..

I'll get some scans tomorrow. Smokey was quite the inventive character.

-Mindgame

 

Do you happen to know the intake runner volume? I haven't seen it anywhere.

 

I'm not able to find much either. I'm surprised nobody has leaked the specs
yet.

Quote Rick Daniel (< ?):
"The first hand-built engine variant to come from the Performance Build Center will be the LS7 OHV V-8 that is the heart of the Z06 performance package earmarked for the 2006 Corvette; specifications and details for the LS7 will be provided at the 2005 North American International Auto Show"


Pic of the head chamber:
http://corvettefever.com/techarticle...04_ls7_5_z.jpg

Runner cut-away:
http://popularhotrodding.com/tech/0504phr_ls7_15_z.jpg

 

Yeah, I have found tons of info, but just not the runner volumes for the intake and exhaust.

 

You would probably be fairly close if you measured the port volumes on the early C5R head P/N 12480005. Configuration is quite similar, with slightly larger valves on the LS7 due to larger bore.

http://www.gmgoodwrench.com/perfpart...Engine%20Parts

 

The C5R port length is actually quite short compared to some 18* stuff I've measured. 5.3" is what I get on the intake length.

400cfm is doable with them as well, getting that flow to be non turbulent is the hard part....

The one big drawback I have found on the C5R heads is the need to have a 4.100" or larger bore to fit the chamber. You could narrow the chamber with some welding and throw new seats in the heads and run a smaller valve, say a 2.08-2.100 on a stock LS1 bore size.

Mindgame has some pics of the C5R castings that he could host that would be cool so we all can see them.

As for the intake port volume of the LS7/C5R style raised runner LS1 heads I would estimate in the 255cc range. The big difference between the two castings is that the LS7 is basically a non canted valve version of the C5R head. The rest of the port layout is pretty close with the changes made to it for the port not having a canted valve.

BTW Pops the Katech Valves in that C5R head were 2.200" to start with they were just cut down at a later date.

Bret

 

You guys are right... it is tough finding information on the C5R. Considering the price castings, I'm not too surprised that no one's really playing with them yet.

Bret,
I believe it was Larry Meaux who posted a mid-port length of 5.875" for the C5R? At least, that's what I have written down here in my "notes" from one of his threads.

I'd really like to see a C5R next to an SB2.2 for comparison. Judging from pics is tough but it seems the sb2 has a straighter line of sight.


That's my thinking too. Seems like a good head for a resleeved build (427+ ci)... would work real well without alot of additional work cause that chamber is BIG.

I have a few pics that I've picked up here and there... one is a raw casting pic (not too pretty) and the other is the CFE heads you referenced in another thread. I'll post them up when I get the chance.

The biggest deal with these heads is going to be in getting an intake on them. One thing I did find interesting is that Kinsler lists their "C5R" intake as a "LS1/C5R" intake. So... does a LSx type intake work on that head or not??

It's an interesting beast and I'm anxious to see someone put together a 427+ ci C5R ultimate-street-type build. Be nice to compare that to something like a big stroker gen1 with sb2.2's on top.

-Mindgame

 

I would have thought that these things were longer as well in port length....

Just remeasured.... 5.55-5.6, which sounds about right to me.

Check your e-mail you have some more pics.

The SB2 port is less prone to turbulence than a C5R port so I wouldn't be suprised if it was a SB2 port crammed into a C5R casting, lots of people I have talked to say so.

I am looking into maybe running these things on a smaller bore, but part of me doesn't want to do that. ughhhh

I have found adaptor plates that bolt a LS type intake to the C5R head, and I have a good feeling that the LS7 intake can work on them as well... Big problem is cowel clearance on a 4th gen, but not on a C5.

Personally I want a 350-370 cube motor so IF I do them I don't want monster TQ, i'd rather have lots of HP since it's only a street car.

Bret

 

See above

 

Where does that info come from?

 

A thread on LS1tech. It is in the LS2/LS7 section. I don't have a link currently. I read it the other morning.