Are MacBook parts of different manufacturing models interchangeable?

I have the oldest possible MacBook (Intel Core Duo Processor) which I have rebuilt, upgraded, and hacked over the years to keep up with all the software updates this modern world has. The only problem I am facing now usually is I need a stronger processor. I am thinking about taking a paperweight Black Intel Core 2 Duo A1181 off a friends hands. They were about to throw it in the pool!!!

I am wondering if the parts between both MacBooks would physically be interchangeable since they are basically the same; only difference really being the processor, airport, and ram capacity.

Basically I want to gut my White MacBook Intel Core Duo and put all of the upgrades into the body of the Black Intel Core2 Duo so I can get a new processor. Is this possible?

Or better yet (probably not), can I simply replace the processor in my current one?