LS4 cam specs
TECH Enthusiast
Joined: Nov 2008
Posts: 622
Likes: 1
LS4 Non Deactivated Cyl.
Inlet Lift 0.482"
Exhaust Lift 0.482"
Inlet Duration 346d
Exhaust Duration 340d
Lift: Non DOD lobes 0.283" intake and exhaust
Lift: DOD lobes 0.289" intake and exhaust
Valve Lift: Non DOD 0.482" intake and exhaust
Valve Lift: DOD 0.490" intake and exhaust
Our ls6 heads are the small valve heads due to the smaller bore, the real ls6 heads will only fit if you bore it out 0.30 oversize or bigger.
Stock valve train operates:
on 1.7.1 rockers which gives you a lift of .482/.490
on 1.8.1 rockers which gives you a lift of .509/.520
on 1.9.1 rockers which gives you a lift of .537/.549
GM has a max limit of .525 for a reason on the stock valve/ spring combination.
Inlet Lift 0.482"
Exhaust Lift 0.482"
Inlet Duration 346d
Exhaust Duration 340d
Lift: Non DOD lobes 0.283" intake and exhaust
Lift: DOD lobes 0.289" intake and exhaust
Valve Lift: Non DOD 0.482" intake and exhaust
Valve Lift: DOD 0.490" intake and exhaust
Our ls6 heads are the small valve heads due to the smaller bore, the real ls6 heads will only fit if you bore it out 0.30 oversize or bigger.
Stock valve train operates:
on 1.7.1 rockers which gives you a lift of .482/.490
on 1.8.1 rockers which gives you a lift of .509/.520
on 1.9.1 rockers which gives you a lift of .537/.549
GM has a max limit of .525 for a reason on the stock valve/ spring combination.
So does that mean that because i put those REAL ls6 heads on my car, they are screwing it up?
Sorry if i sound like a broken record but i seems that this new info is the first i heard about the heads being different.
Sorry if i sound like a broken record but i seems that this new info is the first i heard about the heads being different.
Last edited by Sittingmongoose; Dec 8, 2009 at 07:22 PM.
TECH Enthusiast
Joined: Nov 2008
Posts: 622
Likes: 1
It would depend on whether they have the large valves or not. With the stock bore the large valve (intake valve does not have enough clearance to the cylinder wall), also a different head gasket has to be used for clearance. If I remember correct the large valve (intake) is 2.02"
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Damn, that's a small duration set of cam lobes
Did you mean to type 246 and 240? Must be measured at .000 or .006.
"cheers:
Did you mean to type 246 and 240? Must be measured at .000 or .006.
"cheers:
So if this is right, the difference in the ls4 and ls6 cam should be HUGE meaning i should see some monster gains like 40-50 hp with the ls6 intake considering they gained like 15hp just going from and 01-02 ls6 cam in corvettes.
the difference wasn't just the cam. It was also from a lower restriction airbox and an unscreened maf. But you are right the 01 vs 02 is about 10hp. Now considering the gains over an LS1 cam is about 25hp, going from the LS4 cam to the LS6 cam should be at least another 10hp. So I'll say 30-35hp. You also have to take into account the smaller displacement engine and smaller intake valve.
Here's a good read about the LS6 changes:
http://www.idavette.net/hib/02ls6/index.htm
Here's a good read about the LS6 changes:
http://www.idavette.net/hib/02ls6/index.htm
Last edited by JDMC5; Dec 8, 2009 at 11:39 PM.
