I am currently rebuilding a 2.1L into a 2.2L, and converting it to go into a 1.9L spot in an '85. I have problem, though...

  I have found conflicting information regarding the Cylinder heads between 1.9L and 2.1L waterboxers. Are they indeed the same?  Are the chambers the same volume? The 2.1 heads I have both have a LARGE crack between the valve seats... ...larger, I think, than the Bentley says is allowable. I have a set of "original" 1.9 heads from an '84 that may need to go on in their place.  I do not want to raise my compression ratio - no premium for me, thanks!

  Everywhere I look to find new/replacement or rebuilt heads list the same number for both.

  Thanks to all!