446ci with LS7 Heads
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.
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.
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.
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
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
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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).
Last edited by JakeFusion; Jun 30, 2006 at 12:46 AM.
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.
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?
Yes, you can use the Camaro headers.
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.
does the duration get into account when measuring the spring ability to handle lift?
thanks.
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.
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?
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
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
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"
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"
Jason, is that the same spring you use in the LS7 heads?





