SLED28

iTrader: (7)

It'll be interesting to see what Jesel will do with the cupped rocker stands... I wonder if they can make shaft that goes right across, or if they might have to be milled flat...

383ss

iTrader: (14)

interesting where this is going...

my 5.7L heads peak at about 310cfm at .600 lift and basically level out. I'm putting in a .679 lift hydraulic roller cam with jesel rockers and morel lifters. the cam was spec'd out by a very resepected guy. I was quite suprised by the lift. I'm not going to divuldge any other specs though. I'm also running a vic-jr intake. should have results in the next week or so.

Nickn20

I will be putting together a 422 with ET LS7 heads and a massive solid roller cam very soon, it is ground for nitrous but I still think its gonna rock on motor, compression will be about 12:1. I can't wait! oh and yes ET can set you up with some Jesels for LS7 heads from what I understand, I am gong with a 1.65 ratio rocker to keep lift down in the 690 range.

SLED28

iTrader: (7)

So you are adding a cam and lifters only? What did it make previously? Keep us posted, it'll be interesting to see

383ss

iTrader: (14)

I'm going from a 246/250 .632 FMS cam with melling lifters and jesel rockers to this cam with morel lifters and the same rockers.

before my dyno graph would drop off pretty bad about 6800rpm. I'm hoping the morels will help carry it out some.

Haans249

iTrader: (24)

This is some very good information guys. Dap, I definitely do want to run as high lift as possible, and I think lift at .655/.659 will be pretty good for this setup. I'm also running the PSI springs/retainers from Katech, and they have been tested up to 7600 rpms completely stable on the XER lobes. These springs are extremely light, and have good pressures with max lift at .700". I think the springs weigh in at 68 grams a piece and the retainers are only 5.5 grams. Thats only 73.5 grams per spring/retainer per valve...plus sodium filled exhuast and Ti intake valves. For comparison sake the Comp 921 spring alone weighs 91 grams, so thats saving TONS of weight on in the valvetrain realm. I honestly feel that I could run higher lift and be alright, but to play it safe I'm going keep with the XER's and these put me right about the right lift.
I will be going solid in the future, but thats probably a good 1.5 yrs away because I'm going to be gone for a year overseas here in a couple months.
SLED28, you can mill the rockerarm stands on the LS7 heads flat to accommodate the Jesel offset rockers.
383SS, I think you will manage quite a bit more power with your higher lift cam, but I also hope that the dur's have gone down quite a bit, because to make best overall power, you're going to want your dur to drop 6-8 degrees on the intake side depending on the lobe thats going to be used. Sounds interesting, and you should definitely keep us posted on the results.
Remember guys, huge durations don't necessarily mean more power.

Best Regards!
Adrian

383ss

iTrader: (14)

the duration isn't huge at all. its in my 408 and the duration is in the 24X range. intake and exhaust

Haans249

iTrader: (24)

Based on the flow of your heads, a 240's duration will be fine, I figured you were going to bump dur as well. It should make great power, and it will be VERY interesting to see how just an increase in lift will have on hp/trq. I bet with that higher lift, that your dur at .2 will increase, probably by about 2-3 degrees, and right there, we can see that higher lift will mean more dwell time in the upper cfm lift ranges on your heads and more power....great work.

Beast96Z

iTrader: (21)

In some instances. Alot of the guys with poorer flowing heads and no intake/exaust flow have to go with bigger durations to help make up for the other hindered area's. Hence the reason the T-rex and other big cams do quite well in cam only applications. It's really application specific, which I'm sure your aware of. Man, I think your learning just enough to get yourself in trouble.

JakeFusion

iTrader: (7)

Cartek's 441-447cid engines usually come with a 260/260 114+0. I'm not sure of the lift, but engines that run that cam make damn near 600rwhp with LS6 heads and a FAST 90 intake manifold.

Like Beast said, an engine like that is starving for air, so huge duration with a wide LSA makes great power on such an engine. But you need to run very high compression--12.5:1 at least.

The LS7s will need less to do more. However, I think you are on the right track. If you were running less head and a more restrictive intake, I'd say the concern with overcamming could be tossed out the window. With that said, I would run a 248/258 on a 110 straight up. I don't know what Comp has in the XFI lobes, and I don't think I'd run the LSKs on the LS7 unless some really good hydraulic springs come out that can handle it.

I'd look at Futral, Mikey @ Rapid, or Ed Curtis for a camshaft or Cartek, Vette Doctors, or A&A Corvette (since they have a lot of experience with engines that big).

ringram

A higher lift reduces valve shrouding, duration wont.

Haans249

iTrader: (24)

Jake, good info. Its a very good comparison when seeing how a well flowing setup doesn't need huge durations, and how lower flowing ones do.
Reason why you need such a high SCR with the huge duration is it will bump your DCR and make more power.
As far as the XFI Lobes, I would have used those, but I've read and have been told that they have pretty bad harmonics on the larger durations in the higher rpms, so I opted out of those for valvetrain stability reasons. I also plugged away at the numbers quite a bit, and finally decided on the XE-R lobes at 242/255 on a 113+2. This will get me a DCR of ~8.3 and lift ranges beyond the peak flow lift, hence more "flow dwell time" in the higher lift ranges. Plus, the PSI springs/retainers I'm using from Katech have been proven safe on the XE-R lobes on the Optron so that is some very useful information. I honestly believe this will be a 600+rwhp engine once its all complete. I'm also running 11.5:1 CR FYI.

Beast96Z

iTrader: (21)

I really think you should check with a vendor on that exaust lobe. The reason I keep saying this is because Comp would NOT grind me a XE-R bigger than 248 PERIOD. Another thing that makes me wonder is the guy quoted you odd number durations. XE-R's come in even durations, not odd. Just seems kinda fishy to me. In the end, your specs came out close to mine. I ended with a 243/252 .653"/.644" 110+0, but I'm shooting for the best N/A HP.

Haans249

iTrader: (24)

Honestly....you're making me worried haha. I will have a connection of mine give the higher ups a call on monday and get a final word. I really wish they would print an updated cataloge with all of the "off-the-books" lobes that they have. It really makes it difficult to spec out a cam when you don't have all the tools at your disposal.

I'm also VERY curious as to why COMP would make the LSK lobes all the way up to the 260's duration. If the LSK is so much more extreme then the XE-R, and they won't run the XE-R over 248 "PERIOD", then it doesn't make sense to have the LSK lobe run so high because you'd think that a mid 240's on the LSK would "destroy the valvetrain" and they wouldn't make it. So, I don't see any reason why on earth they wouldn't make the XER all the way up to 260's dur as well....

It also sounds like you talked to the same guy I did, he was really brunt with me and liked to use the word PERIOD quite dramatically.

Is that an LSK intake lobe I spy there?

Abdullah

iTrader: (2)

Jason, i wanted to ask about your springs for the LS7 heads, what is the maximum lift they can handle?

does the duration get into account when measuring the spring ability to handle lift?

thanks.

Katech_Jason

iTrader: (19)

.700

I think I understand what you're asking here so here's my answer. From a standpoint of coil bind, no duration does not matter. Lift, duration and lobe design do play a factor in spring longevity though.

Beast96Z

iTrader: (21)

I understand what your saying. It was over a year ago when I tried to order a cam bigger than 248, so things might have changed, but the numbers just sounded funny. It's really the whole odd number thing that stood out to me. If they do say it is a XE-R, then I would get a lobe number and see what you can find in the catalouge. As for my cam, yes, it's a LSK intake with a solid roller exaust.

Jason, since you guys are dealing with the PSI springs, is there any chance you have the specs for the 1225 springs? I've searched all over and can't find anything. Thanks

Katech_Jason

iTrader: (19)

O.D.: 1.445
I.D. Outer: 1.060
I.D. Middle: N/A
I.D. Inner: .775"
Seat Pressure: 140lbs.@1.950
Open Pressure: 435lbs.@1.200
Rate Lb./In.: 393
Retainer Step: .070"
Max Lift: .750"
Coil Bind: 1.100"

Abdullah

iTrader: (2)

Jason, is that the same spring you use in the LS7 heads?

Katech_Jason

iTrader: (19)

No


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