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Discussion Starter · #1 ·
I mocked up the motor tonight and came up with the following clearances:

Crankshaft endplay: .0055
rod-to-rod gap: .020
piston to deck height: .020

The one i'm looking at is of course, is how far the piston is sitting in the hole. With the Fel-Pro 1074s, I end up with a .059 quench height; not good.

-Should I zero deck the block to get the quench down to .039? Or should I just use the .029 Impy gaskets and only drop my quench down to .049 and will that be tight enough on the 8-10 lbs of boost I plan on running?

- If I need to deck the block, can I do so without distorting the cylinder bore, or do I need to have the torque plate hone redone as well?

-Tightening the quench of course will raise my compression, but i'm going to open up the head chambers from their current 52 CC to around 58; giving me 9.2 to 1 on the .029 gasket or 9.4 to 1 on the decked block option.

To summarize, which is better. 9.2 to 1 w/.049 quench (.020 deck height) or 9.4 to 1 w/.039 quench (zero deck height)?

Cheers,
John
 

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My set up is cnc chamber stock heads(cc ??), srp dish pistons(22-24cc's), and a .005 deck height and stock lt1 gaskets. The cr is supposed to be 9.2. Its holding the 14lbs of boost. I have a aftercooler with a larger resevoir. I would not run more than 8psi if you dont have an intercooler.
 

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Discussion Starter · #3 ·
With your factory gaskets measuring at .051, that gives you a quench height of .056; which dramatically increases you potential for detonation. You final compression ratio is good, but I would go with a thinner gasket and get that quench height down.

I am actually decking the block to .002; with a .039 gasket the quench coems in at .041. I'm opening the head chambers to 58cc, giving me 9.4 to 1 compression. It's all about curbing detonation/keeping the intake charge as cool aspossible.
 

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You know its only detonated once that I can remember and 20k miles. I am gonna guess that I got some bad gas. Thats a hard trade off between CR and quench height. Remember that static compression has a exponential effect on the overall amount of boost that you can use. Yours is safe for 8-10 lbs.
 

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Discussion Starter · #5 ·
And Dynamic Compression would be as equally important. My SCR will be 9.4 to 1 but the dynamic is 8.5 to 1. Which is more important and why?
 

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whats you cam looking like and do you need to pass emissions?
 

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Discussion Starter · #7 ·
The cam was custom profiled by More Performance using Comp Cams Xtreme lobes (and emissions compliance is necessary).

LT1 3314/ 3316 HR115+3

lift- .502/ .520 (@1.5)

Valve timing @.50- open close
int: 0 btdc 44 abdc
exh: 56 bbdc 0 atdc

The specs are for cam installed @112 ICL
Dur- 224/ 236 (@1.5)

Lobe seperation 115 + 3 degress adv. ground in
 
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