Compression in M42 with S50 Pistons

[flyingbrickperformance]

Anyone know what the compression is when the S50 pistons are used in the M42 assuming the piston over deck is the same?  I'm not sure how different the dish is in the 2 so I'm assuming there will be some change in the compression once these are added, especially since its a larger piston.  

The main question is do I need to increase rod length to raise the piston top so that I have more compressioin/better squish.  This would require that I shave the piston slightly which I'd like to avoid, so if the compression of the S50 at 10.5:1 is going to drop to 10:1 when I drop them into the M42, than I'm fine leaving them as is.  If it drops much below this, I'd want to shave and bring the compression back up.  Unfortunately, I have no idea how different the cylinder head chambers are so it makes things a bit difficult.

If anyone has any ideas, let me know.  Its all for experimentation but I'd like to have pretty solid numbers if possible.

[Abrax]

I've calculated some time ago that 2mm lower pistons would drop C/R to about 8,5 : 1...

But theese are not the exact numbers - I have to check it :-)

[flyingbrickperformance]

What were the base specifications of your calculation?  I can probably get to the right number if you have the right numbers available.

[AL GReeNeRy]

i believe kowalski had a stroker kit for sale with machined s50 pistons.  you might want to send him a pm.  iirc he said with the crank he had it kept the stock compression

[Abrax]

I will search for that calculations -;)