This is an example of why it pays to do your homework...... and really be sure of what you’re buying.

The early version of the KB400 had a positive dome volume.
They changed it at some point, and the one listed in the 2016 catalog shows the dome volume as “0”.

I believe the dome got smaller and the valve pockets got bigger.

What that means is...... if you have the “0” dome volume version in your zero deck +.030 over 383 with a 1009 gasket and 84cc heads...... you don’t have a 10:1 motor.

It’s a 9.36:1 motor.

Even swapping out the KB’s for the Icon piston with the 4.5cc dome...... it still only gets you to 9.78:1.
Take the heads down to 82cc’s...... and then you’d be at 9.98:1.