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Ok so just wanted to know a couple things.
How big are the chambers on the L92 heads.
Also how much can I mill them down?
What would the compression be with L92 heads and a 4.03 bore with a stock 6.0 stroke and a factory thickness head gaskets?
And lastly how well do you think a set of L92 heads with some port work and a mill and valve job would do with nitrous compared to a set of 243's also with some port work and a mill and valve job?
I am gonna go GMFullsize on you.......
What are you stupid? Search button don't work!?!
Tired of spoon feeding info to everybody!
:lol:
Sorry, I don't know bud.
:cry: I hate you.Quote:
Originally Posted by tanz45
I tried the search button but couldn't find anything about the chamber size. :(
Found 70cc on google, is that right?
Maybe I'm googlin wrong....can't seem to come with anything. :(
yesQuote:
Originally Posted by tanz45
If you check the gmpp website and view their catalog I think in the acrobat reader download, it will give you some info on those heads. As for milling I think I remember something about their deck being thinner. Anyone else know about that?
L92 heads have 72cc chambers and that the L92 heads have a very thin deck (thinnest of all LS heads) and not to deck them. They flow really well out of the box but at the cost of deck thickness. And depending on the setup and cam... the piston may have to be cut or else piston to valve slap will occur. Lot's of variables with these heads on some setups that make power
Ok well I did a little more looking and ran some numbers.
From another thread...every .006" you mill that's about 1cc...so using that formula milling .020" would take away 3.3cc bringing the chamber to 66.7cc. Milling .030" takes 5cc bringing the chamber to 65cc.
Also I was looking for gasket thicknesses and found some say use .043" and some say .060" so too that into account also. Along with different piston selections...flat tops or dished (-8cc).
So here are the numbers:
Milled .000" w/ .060" gasket and flat tops = 10.19:1
Milled .000" w/ .043" gasket and flat tops = 10.61:1
Milled .000" w/ .060" gasket and -8cc = 9.39:1
Milled .000" w/ .043" gasket and -8cc = 9.73:1
Milled .020" w/ .060" gasket and flat tops = 10.58:1
Milled .020" w/ .043" gasket and flat tops = 11.03:1
Milled .020" w/ .060" gasket and -8cc = 9.7:1
Milled .020" w/ .043" gasket and -8cc = 10.07:1
Milled .030" w/ .060" gasket and flat tops = 10.79:1
Milled .030" w/ .043" gasket and flat tops = 11.26:1
Milled .030" w/ .060" gasket and -8cc = 9.87:1
Milled .030" w/ .043" gasket and -8cc = 10.26:1
That's a lot of typing on my iPhone. :lol:
Anyway back to my OP...we know with P&P the L92's out flow just about everything so what are the thoughts on these vs. 243 heads on a nitrous motor?
Of course you would post this while I was doing my research and typing that ^^^ out :argg:Quote:
Originally Posted by mean05
Lol that's some good numbers you came up with though. IMO don't deck ANY set of heads more than .010 especially under nitrous.
why would you say that?Quote:
Originally Posted by fullthrottle
Just doesn't give you much room for error especially for a DD. Let's say heads gotta come off if a lifter goes bad then you gotta deck them again and find that they're super warped cuz they are already thin. Might as well junk them. Aren't nitrous motors more prone to electrolysis as well? Yet another reason I would be wary.
Wondering the same thing....Quote:
Originally Posted by mean05
Quote:
Originally Posted by mean05
i dont know about the 6.2 but on a lq9 ( 4" bore ) to get my compression where i wanted it ( 11.1) i had my heads milled .015 then used a .040 gasket. virgil is correct when it comes to the overall setup, i do plan to spray a 150 shot probably at end of year or early next year ;) right now with a few extra mods i have done i am putting down 470 to the wheels.. my future plans though would consist of a new cam, and the ls3 fast intake and bigmouth TB. and a little something else, just gotta see how it works out, my goal has always been 500 rwhp, and as close as i am now i feel i can achieve it.
anyone know exactually what the difference in thickness is?
Travis you got a PM regarding prices on these heads, I cooked you up a decent deal.