just wondering what options i have in replacing my 325 engine with a bigger engine such as a 500 or something and still be able to use my same tranny and framework/ body plastic

my 325 went out and it seems that i can find some 500's online cheaper than repairing the 325

 

It would be cheaper and easier to find a 325 or 330 to use.500s will fit but hey are water cooled and you would need the complete cooling system