915 to edelbrock performer rpm hedas, bad idea?

Hi! first post on this forum :-) I have a question about compression.
I've got a rebuilt (at least what I have been told) -67 440, 030 over, steel crank, forged pistons (stock replacement), 915 heads (1.60 exhaust) :-(. Was told it should be about 9.8:1 compression (shouldn't it be 10.1:1 if it's built with stock replacement pistions?)
Cam shaft is Comp extreme energy XE268H
My plan was to replace the 915 heads with aluminum Edelbrock performer rpm 84cc heads
would this work, what about compression will it drop too much, would this be a performance loss or would I gain hp?

Thanks!
Lars
Author: xmoparx