The vaccum module ion the IP is a bleed valve.
Are you changing out the motor and tranny or just the motor?
if just the motor and your 80 does not use the vacuum module then no big deal. If your 80 is like mine you need this bleed valve for the tranny to shift correctly.
If the IP's are the same mw style then it is fairly easy to convert the top plate on the IP to match teh one that was in the 80. Issues may come up if the throttle shaft does not have teh fitting for the push rod that connects to the vacuum bleed valve.
I just did a conversion on a pump that was not so equiped and it was no big deal but if the two pumps are in fact both MW's then you can just switch teh pumps and be done with it. If you need to switch the shafts also I can walk you through how I did mine but be prepared to go inside the back cover and r&r parts between the two pumps. I was nervous when I did it but it turned out to not be a big deal once I finished... Oh, and it worked
If you need more info let me know.