Quence
Changed mine bto .032. I put .028 thinking of the wrong gasket thickness.
Last edited by WhiteRhino; May 27, 2009 at 01:12 AM. Reason: wrong number
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No joke, the tighter the better. Here is the thing though, u need to know true deck height, compressed gasket thickness, bore size, and piston to wall clearance hot and cold.
Let take a 346 ls1 (typical), we find the piston is out the hole .006, and we want to use a .041 gasket. Taking the .006 from the .041 we end up w/ .035 clearance. If u used a forged piston u will find it "rocks" in the bore at tdc and u can measure this.If u had a gasket too thin, the piston would hit the head at tdc, because the piston "*****" in the bore as it changes direction. U will find that u need at least .032 clearance to keep the piston from hitting the head (so the .041 will work but a .031 would not). I used to use .029 gaskets on the sbc and would cut .004 off the edge of the pistons in the bridgeport. Carbon could never build up on the flat portion of the head next to the chamber, cause the piston was so close.
Why do u want this? The engine will be less prone to detonation (even having a higher static comp ratio), will tolerate more timing, and will have higher peak hp/tq #s. I don't care if it runs on 87 octane or 116, the results will show on the dyno everytime. I can get u 12-15hp AT THE REAR WHEELS w/ a head gasket ONLY change on the LS7. Guys are running 12:1+ comp. ratios and 91 octane w/ no issues, proper quench is a major key not to be overlooked.
No joke, the tighter the better. Here is the thing though, u need to know true deck height, compressed gasket thickness, bore size, and piston to wall clearance hot and cold.
Let take a 346 ls1 (typical), we find the piston is out the hole .006, and we want to use a .041 gasket. Taking the .006 from the .041 we end up w/ .035 clearance. If u used a forged piston u will find it "rocks" in the bore at tdc and u can measure this.If u had a gasket too thin, the piston would hit the head at tdc, because the piston "*****" in the bore as it changes direction. U will find that u need at least .032 clearance to keep the piston from hitting the head (so the .041 will work but a .031 would not). I used to use .029 gaskets on the sbc and would cut .004 off the edge of the pistons in the bridgeport. Carbon could never build up on the flat portion of the head next to the chamber, cause the piston was so close.
Why do u want this? The engine will be less prone to detonation (even having a higher static comp ratio), will tolerate more timing, and will have higher peak hp/tq #s. I don't care if it runs on 87 octane or 116, the results will show on the dyno everytime. I can get u 12-15hp AT THE REAR WHEELS w/ a head gasket ONLY change on the LS7. Guys are running 12:1+ comp. ratios and 91 octane w/ no issues, proper quench is a major key not to be overlooked.
And "12:1+ comp. ratios and 91 octane" is that still referring to the LS7? I like those numbers
No joke, the tighter the better. Here is the thing though, u need to know true deck height, compressed gasket thickness, bore size, and piston to wall clearance hot and cold.
Let take a 346 ls1 (typical), we find the piston is out the hole .006, and we want to use a .041 gasket. Taking the .006 from the .041 we end up w/ .035 clearance. If u used a forged piston u will find it "rocks" in the bore at tdc and u can measure this.If u had a gasket too thin, the piston would hit the head at tdc, because the piston "*****" in the bore as it changes direction. U will find that u need at least .032 clearance to keep the piston from hitting the head (so the .041 will work but a .031 would not). I used to use .029 gaskets on the sbc and would cut .004 off the edge of the pistons in the bridgeport. Carbon could never build up on the flat portion of the head next to the chamber, cause the piston was so close.
Why do u want this? The engine will be less prone to detonation (even having a higher static comp ratio), will tolerate more timing, and will have higher peak hp/tq #s. I don't care if it runs on 87 octane or 116, the results will show on the dyno everytime. I can get u 12-15hp AT THE REAR WHEELS w/ a head gasket ONLY change on the LS7. Guys are running 12:1+ comp. ratios and 91 octane w/ no issues, proper quench is a major key not to be overlooked.






