moekluse

iTrader: (2)

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

MuhThugga

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.

JoeNova

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

MuhThugga

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

moekluse

iTrader: (2)

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

gagliano7

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

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

wannafbody

iTrader: (2)

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

moekluse

iTrader: (2)

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.