m477

I'm daydreaming about a fun N/A build with a 6.0L LS2/LQ4/LQ9 block and L92/LS3 heads, and I was curious about compression ratio. Other LS1Tech guys use this calculator:
http://www.csgnetwork.com/compcalc.html

The problem is: I'm not sure what head gasket to use, so I can't fill out all the fields on the calculator form. Would I use 4.00" bore gaskets to match the block, or 4.06" bore gaskets to match the head? And why?

I know that question may be a little vague, so I made this (admittedly very crude) diagram to show my concern.

H = head, B = block, P = piston.

The red and blue lines show where a head gasket would be; the short blue lines represent a head gasket designed for the head's larger bore (I think) and the longer red lines represent a head gasket designed for the block's smaller bore.

Would I use the red gasket or the blue gasket?

pwrtrip75

iTrader: (8)

You want the fire ring on the gasket to NOT be exposed... so you would use a gasket to match the head. Like using 6.0L heads on a 5.3 you use the 6.0 gaskets.

The red lines would be bad.

m477

Thanks for the quick response and the explanation!

Is it possible to do the opposite -- put smaller heads on a larger-bore block? 5.3L or 5.7L heads on a 6.0L block? If I were to do that, which gaskets would I use?

johnjzjz

normally you cant do that -- the piston needs the min of .040 to any location on the head so it does not make contact if it does the bearings go right out of it - jz

batboy

iTrader: (6)

GM head gaskets are .051" thick if you need that spec for the calculator.