Ported L-92 Heads
Ported L-92 Heads Does anyone sell a set of ported and built up L-92 heads yet? If not and I bought a set from GM would anyone be able to port them? How good are the springs and retainers in those? I figure they should be replaced since I was planning on going with a big lift cam (.600+) but if the stockers are up the task why bother. Should the valves or anything else be changed? I think they are 2.16/1.59 out of the box from GM. 
Banned - Ed Curtis aka EDC
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Originally Posted by JASON11WS6
Does anyone sell a set of ported and built up L-92 heads yet? If not and I bought a set from GM would anyone be able to port them? How good are the springs and retainers in those? I figure they should be replaced since I was planning on going with a big lift cam (.600+) but if the stockers are up the task why bother. Should the valves or anything else be changed? I think they are 2.16/1.59 out of the box from GM.
Toss the OEM valvetrain and get what matches the camshaft. Plan on good parts to maintain valvetrain rigidity.
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Originally Posted by JASON11WS6
Does anyone sell a set of ported and built up L-92 heads yet? If not and I bought a set from GM would anyone be able to port them? How good are the springs and retainers in those? I figure they should be replaced since I was planning on going with a big lift cam (.600+) but if the stockers are up the task why bother. Should the valves or anything else be changed? I think they are 2.16/1.59 out of the box from GM.
Here's the best part...this level of performance will easily be under $1k
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Is having such a big intake runner volume going to hurt people like me who want a daily driver type car? That thing is going to be in the 260's after porting. Can the cam choice help balance this out?
-Geoff
-Geoff
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Originally Posted by White_Hawk
Is having such a big intake runner volume going to hurt people like me who want a daily driver type car? That thing is going to be in the 260's after porting. Can the cam choice help balance this out?
-Geoff
-Geoff
Yes, I'm guessing these things will make big power with less duration than we normally see, especially with smaller cube motors. Especially since the ports are a little big anyways. Starting with a LS2 block is all you need to do. I have a feeling that the large valve for the bore and the large cross section normal rules that apply might not apply here with these heads. With these things 400 cube motors should be able to make power till 7000rpm without too much issue. These heads are just too dam good in terms of velocity profile AND chamber shape.
Originally Posted by JASON11WS6
Can I get a little exrtra info?
Bret
It's a L76 motor in the Holdens and it looks like a LS2 block with the L92 heads and Aussie intake. I haven't heard anything from them, but they seem to undercam that motor crazy for emissions and to stay below the power output of the LS2. Got me as to why. IMHO the sheetmetal stuff is for big cube race motors, we will see the L76 intakes here at one point, just gives more time for developing the head ports.
Bret
Bret
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From: TAMPA by way of MIAMI!!!
Sooooo it looks like we still gotta wait to get them here to find out if they are worth a schizzz. Well as long as they flow at least LS6 style we should be good. Right?
Quick question just how bad does an LS2 manifold flow? I've seen here that they don't flow very well but thats all relative right? I mean the LS6 flows better than the LS1 but the LS1 really doesn't flow that bad, does it?
I need to have this clarified if anybody has the patience and or time. Thanks
Quick question just how bad does an LS2 manifold flow? I've seen here that they don't flow very well but thats all relative right? I mean the LS6 flows better than the LS1 but the LS1 really doesn't flow that bad, does it?
I need to have this clarified if anybody has the patience and or time. Thanks
This GMHTP article should at least give us the numbers on the manifold and stock heads.
https://ls1tech.com/forums/generation-iv-internal-engine/565248-livernois-motorsports-tests-gm-l76-l92-carb-manifolds-gmhtp-magazine.html
https://ls1tech.com/forums/generation-iv-internal-engine/565248-livernois-motorsports-tests-gm-l76-l92-carb-manifolds-gmhtp-magazine.html
The heads are already smaller chamber volume than the 6.0L heads so it's a better place to start and yes they can be milled more, we have to get them at least to 60-62cc for them to be worth a **** on the LS2 stuff.
As far as the GMHTP article I doubt it's going to tell us more than we already know.
The intake should flow more due to the 25% larger cross section of the intake over the LS6, if it flows half of that % gain more than the good LS6 stuff then we should see over 310cfm thru the manifold which would be a huge improvement.
The only thing that worries me about these castings is the large cross sectional area, but the valve area relative to the cubes on the 6.2L is right in line with the LS1 and LS6 so the port has to be proportional to the valve. That plus this is a much better port design.
Bret
As far as the GMHTP article I doubt it's going to tell us more than we already know.
The intake should flow more due to the 25% larger cross section of the intake over the LS6, if it flows half of that % gain more than the good LS6 stuff then we should see over 310cfm thru the manifold which would be a huge improvement.
The only thing that worries me about these castings is the large cross sectional area, but the valve area relative to the cubes on the 6.2L is right in line with the LS1 and LS6 so the port has to be proportional to the valve. That plus this is a much better port design.
Bret
