It's pretty simple actually. Just check the port positions and make sure they are the same on the top you're going to swap onto the base. If not get ready to do some line bending or obtain a compatible top. I did a similar swap with an angle top & straight bottom. I make it work by turning the top to line the ports up, which ended up twisting the diaphragm. It worked for a while but soon the diaphragm gave up the ghost. If you have a good hole punch set you might be able to re-cut the screw holes in the diaphragm & avoid the twisting. I don't have a punch set so I hillbilly engineered as noted above. Won't do that again.

Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.