G'day Zonker, motor wise most of the parts are interchangeable A10 to A10, A7 to A7 bar the early long stroke. The cases for a '54 swing arm are the same as a '63 A10 and A7 the same. The only difference between A7 and A10 is the head + valves,barrels,pistons,rods,crank and push rods.
An alloy head will fit where a cast iron was (different bolts), thick flange barrels replace thin flange (longer studs required), large journal crank and rods replace small journal. Have fun.
Cheers