79 invader squish

[gixxer6]

Interceptor398

[Kal k]

So what's the difference between the 398 and the invader heads? And how much did you shave them?

[gixxer6]

Interceptor398 is a member on this forum.  He cut my Invader heads for me. 

[Kal k]

Haha ok now I'm getting what your saying. So do u know how much got shaved

[Interceptor398]

1mm of the face and squish area but none off the dome.  Aaen trial spec.

[Boomologist]

Question:Taking 1mm off the head just lowers the dome thus raising compression? The reason to take material off the squish is to prevent detonation? Couldn't the same effect be accomplished by leaving the surface and squish as is and building up material in the dome?

[gixxer6]

Question:Taking 1mm off the head just lowers the dome thus raising compression? The reason to take material off the squish is to prevent detonation? Couldn't the same effect be accomplished by leaving the surface and squish as is and building up material in the dome?

"Squish is an effect in internal combustion engines which creates sudden turbulence of the fuel/air mixture as the piston approaches top dead centre (TDC). In an engine designed to use the squish effect, at top dead centre (TDC) the piston crown comes very close, (typically less than 1 mm), to the cylinder head." 

Material is removed from the gasket surface, then the same amount of material is removed from the squish area.  This keeps the squish distance the same.  So yes, adding material to the dome would have the same effect.  But it is easier to remove material from the gasket and squish areas than it is to add material to the dome.