I remember reading a thread a long time ago about the detrimental effects of loosing the "squish" area on a cossie head due to over-machined heads etc, and just out of interest, how badly would affect the burn/ combustion chamber shape etc if you used one of those copper head gaskets ( is it vulcan that do them? ) to get back down to the correct compression ratio? Without having the tools to hand to work out CC's of combustion chambers etc, how thick would the headgasket need to be made extra to drop the C/R from say 8.0 to 7.5??

Long studding the 200 block- if the block is long studded in all 10 places, does the water pump have to be modified? I seem to remember reading it somewhere, but it might be complete bollox

Any help with the above mucho appreciated

 

You cant really take a lot of CC's out of a pentroof designed chamber very easily even with the tools TBH, you can get some out of it, but not enough for big changes in CR.

Dropping from 8.0 to 7.5 will need nearly an extra MM on the gasket.

Squish will indeed be effected, potentially meaning you have to run slightly less timing to avoid det, but i personally doubt it would be an issue on a moderate spec YB, they arent exactly cutting edge design on squish anyway, but i havent tried it personally myself so you need to talk to Stu or Karl really, as i only know it will effect it, but i dont know exactly how much by like they will as know doubt they have both mapped an engine like that at some point.
I would strongly recomend avoiding any off the shelf chip for such an application though and would suggest you get it livemapped by someone like Stu or Karl.

 

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