Does anyone know more specifics (chamber size, etc...) about this head casting: 6272292

Here's what Mortec says, "6272292....70-78...oval...OPEN...402, 454"

I want to transplant these onto another shortblock and want to figure out what compression ratio I'll have. Thanks.

I believe those are LS-3 LS-5 270 hp heads should have 118cc chambers. my best guess