X heads on a 360?

Hello friends. I recently picked up a very nice set of 340 x heads that have been very nicely ported. I have a low mile 360 out of a 78 d200 I'd like to slap together and get rid of the smog heads my bottem end is in great shape and no need to rebuild. Will the x heads work well on this block? I know they will bolt on but what I'm asking is will this kill my compression? Thank you in advance