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Does anyone know for sure what the combustion chamber size is for the LS3/L92 head? Some publications say 70cc and others say 68cc. Also does any body know for sure how much I need to mill the head to get a 65cc chamber? I have read .025 and also read .030. Is the "rule of thumb" .006 per 1cc? I'm putting my LS3 heads on my LQ9 6.0 and I want to run 10.9 compression , same as LS2. thanks
Does anyone know for sure what the combustion chamber size is for the LS3/L92 head? Some publications say 70cc and others say 68cc. Also does any body know for sure how much I need to mill the head to get a 65cc chamber? I have read .025 and also read .030. Is the "rule of thumb" .006 per 1cc?
sorry bud dont mean to jack your thread here just curious,how much can you safely mill off of these heads? i have -12cc pistons with untouched 821s and the power just isnt there, thinkin of millin this winter. would like to get to 11.1-11.5.1 can this be done with milled heads and a thinner gasket than what im using now?(.051)
jason
__________________ 2001 camaro ss # 0907
stock Dynoed 332/345
fully forged 408,LS3 heads and intake,tsp mini stick 235/240 .603/.609 112, slp headers, moser 12 bolt, th400, 3500 stall- gone
New-1985 sea ray 270 sundancer
twin 3.7l merc 4 cyl 170hp a piece
new outdrives, 300hrs on new motors
weird they had to take .014 off my ls3 heads to get 68cc
__________________
2001 Trans Am WS6 l Cadillac Diamond pearl l 416 LS3 l TEA LS3 heads l FAST 102/102 l Compstar crank/rods l Wiseco pistons l Comp LSR custom grind l Kooks 1 7/8 and Kooks true duals l TSP 100mm maf l Becool l MWC 9" and watts link l Real Superhawk hood l Monster stage 3 l Tick Master l Ractronix Fuel Pump l Strano springs l
Most reports I've seen says 70cc, and to get to 68cc you need to mill .012, and for 65cc you need to mill.030. I guess when I take my heads to the machine shop I'll get them to measure the cc first, then mill them .012 and measure again, then mill .018 more (.030 total) and measure again, then we will know for sure.
Michigan Snowmobiler 1969 Firebird: 7.55@92.93 1/8 1.70 60 ft. 11.7@116[/color] EPS cam 234/246 .602.606 114+3, 6.0 LQ4, L92 heads milled 10.5:1, Ported L76 intake, ported 90mm Holley TB, 100mm MAF, FIC Custom injectors, Hooker LT, PYPES dual exhaust with an X pipe, 4L65e with all of the good parts inside, FTI 4000 RPM Stall, 12 bolt with 3.73 gears. HP Tuner tuned by me
I took my ls3 heads to my machine shop friday to have them cc'd then milled and cc'd again, should have them back in a few days and will post the results.
Ok, I got my heads back from the machine shop, stock chamber size was 68.5 cc, they then milled them .030 and the chamber size is now 63cc., stock LS2 has 64.5 cc heads and flat tops and 10.9 compression, my engine should come in about 11.1:1 compression ratio, engine is LQ9 6.0, flat tops. thanks for all the input guys,
Close is fine if you've got a light weight valve and good spring. In that type of scenario I'll run them .050-.060 clearance on the intake without any worries. Those springs were "PSI" springs. Single beehive and will hold .650 all day.
It is LSL lobes. Those lobes work real well with the LS3/L92 heads.
Michigan Snowmobiler 1969 Firebird: 7.55@92.93 1/8 1.70 60 ft. 11.7@116[/color] EPS cam 234/246 .602.606 114+3, 6.0 LQ4, L92 heads milled 10.5:1, Ported L76 intake, ported 90mm Holley TB, 100mm MAF, FIC Custom injectors, Hooker LT, PYPES dual exhaust with an X pipe, 4L65e with all of the good parts inside, FTI 4000 RPM Stall, 12 bolt with 3.73 gears. HP Tuner tuned by me
Last edited by 69LT1Bird; 09-05-2010 at 06:27 AM..
Close is fine if you've got a light weight valve and good spring. In that type of scenario I'll run them .050-.060 clearance on the intake without any worries. Those springs were "PSI" springs. Single beehive and will hold .650 all day.
It is LSL lobes. Those lobes work real well with the LS3/L92 heads.
Cool, what kind of power did that combo put down?
__________________ Who is smarter, the guy with the junkyard budget build or the guy who's mods either equal or cost more than his car is worth?
So wouldn't you better off to try a thinner cometic gasket first instead of milling? That way if your cam doesn't fit no harm done, afterall you cant un-mill your head.
__________________ 05 gto A4, sap grilles and front bumper
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12.80 @ 109.21
LS3 head chamber cc 
