I'm about to start a rebuild but I have a few questions I need answered before I put the block in the shop. First. I know it will be necessary to deck the block to achieve flatness but is it necessary to zero deck it? I really would like to keep the compression sub 11.0-1. What is the standard deck on a stock block? Is there minimum amount that the machine can remove? It may seem like a silly question but I really don't know how the machine works. I'm considering going to a 396 stroker but I think the largest dish I can get would be 12 cc. Even with that, I think my compression would still be close to 12-1 with a 54 cc head. Does anyone know the formula for figuring out final compression and what other variables am I going to have to consider?

 

I didn't even realize I posted this in the ls1 section. Sorry, I'll post it in lt1.

 

I'll move it.

 

Stock deck is 0.025". With stock gaskets, this gives too wide a quench area. A better combo is 0.00" deck with a 0.039" FelPro #1074 gasket. There are many online calculators which can give you a CR.

This one doen't include the ring recesses or the gasket bore, but those are minor contributors http://www.rosspistons.com/CR%20Calculator.htm This one http://www.csgnetwork.com/compcalc.html includes gasket bore diameter and this page http://www.kb-silvolite.com/calc.phtml#comp1 calculates a number of other dimensions that are useful.

A block may not need to be decked at all, it depends on how flat and sqaure the deck surface is to the plane of the crankshaft centerline. The make it flat and sqaure, the amount needed to be removed depends how far out it is.

I recommend zero deck with the 0.039" gasket. The block work is done first so you can chose the right piston compression height to give the desired "deck". Chose a piston crown volume to give the desired CR.

Rich Krause

 

IMO, its plain dumb if you dont have the block decked and the heads milled when you do a motor. Dont ask how i know.