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5.3L, needs 12.5:1 - 13:1 compression.

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Old 05-15-2008 | 05:49 PM
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Default 5.3L, needs 12.5:1 - 13:1 compression.

Trying to make a project 5.3L run on straight alchohol, anyone know if they make pistons to meet my compression needs? I can mil the heads and run a thinner gasket if needed. Any help at all is appreciated!
Old 05-15-2008 | 11:31 PM
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They would have to be custom made or you can bore it out to factory 5.7L Spec. and buy over the counter LS1 racing pistons. The only thing avalible for the 4.8 and 5.3 off the shelf is a stock replacement type unit....
Old 05-15-2008 | 11:39 PM
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Isn't the alcohol best kept chilled in a bottle in your hand?

Anywho, research into replacement 4.8L pistons if you're wanting to keep the 96mm bore (I would personally so it can take the abuse) because I read somewhere on here that 4.8L pistons are flat tops compared to 5.3L pistons. I have no specifics, but it's a direction you can check into.

If those do work, flat tops in a 61.15 cc chamber will already send ya into the 11+ compression range. Milling then becomes cheaper because you'll have less to take off, also while making sure you've gone through the motor for a complete rebuild before pounding it with alcohol.

Question...would a motor run on alcohol be required to attend AA meetings?
Old 05-15-2008 | 11:45 PM
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Stock flattops from an L33 with 862s cut to 56ccs will get you over 11.5:1 with a thinner gasket.
Can't go much higher on a 5.3 easily.
cutting more runs into intake fitment problems, and valves start to get pretty close to pistons, etc
I suppose you could weld the chambers...
What is the engine for?
Old 05-15-2008 | 11:55 PM
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The original C5R heads had ~39cc chambers, but I seriously doubt the valves would clear the cylinder walls.
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