12.0:1 cr on 418ci ls3
07-12-2013, 10:12 PM
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12.0:1 cr on 418ci ls3 I am looking to get to a 12.0cr on a upcoming build of a 418 and need help deciding what size of flat top piston to get in order to allow a 12.0:1 car along with my PRC 265cc ls7x small bore heads and cosmetic .040 head gasket. This will be running on 93 pump gas. Thank you guys!
07-13-2013, 07:16 PM
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I hope you're going to have a big cam to bleed off some of that compression or you're going with some steep gears to get that pig (5th gen) moving with 93 octane and 12:1.
07-13-2013, 07:59 PM
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07-13-2013, 08:08 PM
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I would think Minimum 243 dur. @ .50 and a min. of 3.73 or maybe even 3.90 and my car is lighter than (5th gen) G-body also using 4200 single disc stall.He will have a little greater # in torque with Fast or stock intake( Me & Vic Jr.). That is a really heavy car I wouldn't be surprised that they would recommend him something bigger starting at 247 dur.
07-13-2013, 09:28 PM
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That's what I'm guessing as well I'm still waiting on quotes from lmr england green and lethal racing for labor charges since I already have all the parts except for cam pushrods and gears. Got everything ordered last night
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07-13-2013, 10:13 PM
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Call piston manufacturer, they will tell you just the piston you need and what they have or if not they will make them for you, as for cam pay, is only $25. to get it rite the first time Camhelp@guerragroup.com
With that compression, for street you will need E85 IMO, you will prob do better going with 11.5 and running more ignition timing instead, and will else keep engine temps in control.
.040 head gasket is cutting it unnecessarily close piston to head clearance, you can use .051 and obtain the desired compression true the correct piston instead, I suggest boost specific top piston ring if you want this combo to last and use hard tension oil rings to keep combustion chamber dry from oil cause you can't make more power with a low tension oil ring and oil wet spark plugs.
A lot more than you asked but thought you'll appreciate it.
With that compression, for street you will need E85 IMO, you will prob do better going with 11.5 and running more ignition timing instead, and will else keep engine temps in control.
.040 head gasket is cutting it unnecessarily close piston to head clearance, you can use .051 and obtain the desired compression true the correct piston instead, I suggest boost specific top piston ring if you want this combo to last and use hard tension oil rings to keep combustion chamber dry from oil cause you can't make more power with a low tension oil ring and oil wet spark plugs.
A lot more than you asked but thought you'll appreciate it.
07-14-2013, 03:43 PM
#11
No need to pay anyone nightmare, if you go thru LME they will tell you exactly what you'll need like how much to mill the heads cause they'll know what your deck height will be exactly to acheive your desired compression etc etc. When you call ask for Erik from Chicago he's a SAM graduate and works there now. Tell him Zeke sent ya.
