Why would you want to do that to a Stereo Chorus amplifier?
From the block diagram it is apparent that there are two distinct output sections in this amplifier.
So basically what you are saying is that you want to bridge the two output sections.
My gut reaction is "No Way" are you going to safely pull this off by simply connecting the wires to one speaker.
But then again, I have been known to be wrong
To be sure, why don't you call Peavey Tech Support & ask them.