how much do my pistons have to be dished

[00xj74]

Ok so I recieved my pistons today and I need to know how much the pistons need to be dished when the combustion chambers being pollished.

Here are my numbers from the calcualtor

SCR: 10.09
DCR: 8.82
Quench: .0645

This is with a 68-231-4 comp cam and a .043 head gasket

Your help is greatly appreciated

[Cheromaniac]

You'll need to drop the SCR by about half a point, which requires adding 5cc to the total combustion volume.

[00xj74]

What octane fuel will adding 5cc to each combustion chamber allow me to run? Ideally I would like to run 87 or 89, so is another 5cc's added to each combustion chamber be enough to run that octane>

thanks. is it possible to add 5cc to the cylinder head or is that not a good idea.

[Cheromaniac]

I don't know if polishing the combustion chambers alone would be enough to add 5cc. Your chances of success are greater if you do the piston dishes as well. This would reduce the SCR to 9.6:1 and improve your chances of running lower octane fuel.

[00xj74]

So just get the pitsons dished 5cc's more and polish the combustion chambers and i'll be able to run an octane lower than 93