Milling 243 heads for LQ9
This is a discussion on Milling 243 heads for LQ9 within the Internal Engine forums, part of the LSx Technical Help Section category; as many of you have heard my lq9 6.0 destroyed the main bearing a little over 2 weeks ago and ...
05-01-2012, 04:41 PM #1
- Join Date
- Aug 2010
- Oklahoma City, Oklahoma
- Y2K SS CAMARO
Milling 243 heads for LQ9
as many of you have heard my lq9 6.0 destroyed the main bearing a little over 2 weeks ago and now that i have it torn apart i want to beef it up some. one thing i was looking to do was mill the stage 3 243 heads that i currently have. question is i dont know how much they need to go. we only have 91 octane gas here in ok so i will be limited to 11.5 and lower from what i can tell. just looking to get it to over 500 on motor if possible.
the forged internals are stock size so 4.030 bore and a 4.0 stroke just forged for the bottle if it makes any difference
My mods are in my sig
Last edited by WICKEDLS1; 05-01-2012 at 05:28 PM.2000 ss camaro, forged lq9 370 short block, stage 3 PRC 243 heads, fast 102 w, big mouth throttle body, MS3 cam, 1.7 roller rockers, stage 3 t-56, monster stage 3, pro 5.0, 4.10's with moser axles, bmr tq arm, lca's, phb. SOLD (thankfully)!!!
New project: 1968 step-side, partial restore, ls/th400 swap. hopefully boosted pics and more info to come!!!
Having a small cam is like having a small dick, everytime you go to use it you wish it was bigger
05-02-2012, 05:44 AM #2
If you know how many cc's they are you can use this site to get all your specs right...just punch in the numbers you have now, them play with the cc size of the chamber to get the right compression.
Wallace Racing - Automotive Calculators
If you don't have your new pistons yet I'd recomend going with a slight dish, then mill more off the heads to make up for it....this will center more of the combustion forces to the center of the piston instead of out towards the ring lands
06-07-2012, 02:13 PM #3
usiing the calculator above if you ran a 68cc combustion chamber with a flat top piston coming flush with the deck and run a gm mls gasket you'd be right at 11.44 to 1. with the cam your running though not sure if that is possible for you. If you know what your PTV is right now that will def help in letting you know how much you have to play with in regards to gasket thickness, deck hieght and combustion chamber cc. Running a dish like listed above will help PTV issues and allow for more play in your quest for a tighter chamber.2002 Trans Am WS.6 A-4:
Volant CAI, BBK LTs, BBK ORY, SLP LM2, FROST Tune, A/C Heat Delete, AIR Delete
06-08-2012, 05:16 AM #4
If it makes a difference, I'm running 12.5:1 scr on my 408 on pump gas (92-93 octane), but my cam drops my dcr down to a pump gas friendly 8.22:1 dcr the bigger cubes eat the extra duration right up.....I daily driver mine 50+ miles a day with a 255/263 .624/.624 115lsa cam
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