5.3 max compression heads

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Feb 15, 2017 | 07:35 AM

#21

moekluse

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From: Nc

Quote:

Originally Posted by JoeNova

Powell Automotive sells updated 243 castings.
They flow 10% more than the OEM versions.

Otherwise, check craigslist or the classifieds. They're all over the facebook LSX groups.

I'm going to check them out now, thanks!

Feb 15, 2017 | 08:15 AM

#22

MuhThugga

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From: Wilmington, De

Quote:

Originally Posted by moekluse

I have a dished wiseco -10cc piston. I know that doesn't help me bring compression up but it'll bring it up to 9.3:1 which should get the job done

Yeah, those pistons don't help matters at all.

Assuming the pistons come .006" out of the hole, using a Cometic .040" thick, 3.910 bore gasket, you'd be at around 9.5:1 with 61cc chambers. If you shave the heads down to 58cc chambers, you'd be at 9.9:1.

If you are happy with that number, then bravo. Personally, I'd be switching to a flattop piston to get a compression ratio between 10.5-11:1.

Feb 15, 2017 | 08:47 AM

#23

JoeNova

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From: Ohio

He said he's still going turbo. No need for 11:1.

Feb 15, 2017 | 08:51 AM

#24

MuhThugga

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From: Wilmington, De

Sorry. I thought he was still going N/A with the 5.3.

Feb 15, 2017 | 08:58 AM

#25

moekluse

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From: Nc

Ok! 9.5 will work great, I'm going to start looking around for 243s. I really appreciate all of your input guys. Thanks

Feb 16, 2017 | 12:28 PM

#26

gagliano7

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From: Monroe,NY

Trickflow makes 205 heads with 58cc chambers that are made for the 5.3.

https://www.summitracing.com/search/...3l-5-7l-vortec

Feb 20, 2017 | 08:25 PM

#27

wannafbody

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From: Pittsburgh

Dart 205 LS heads, Edelbrock LS heads otherwise get 243. Not gonna matter much if your supercharging or turboing.

Feb 23, 2017 | 01:17 PM

#28

moekluse

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From: Nc

Ok guys, this is where I'm at. My internals were at my machine shop, I went to go check on them and I told him about the compression issue. He told me he's a wiseco dealer and that he can swap out my dished piston for a flat top with valve relief, which would put me at 9.3ish:1 compression. Im really happy he could do that, which means I can still run my 317s but I might bring it up to around 10:1 of I opt for some 243s.

He told me he just got done building a forged 5.3 with same setup and made 1000+ hp to the wheels, he had it set to 23psi but it boost spiked to over 30. Holy crap, and he's running 10.5:1 cr on 110 octane.