Can I replace a cat 3066 motor with a cat 3306 on a cat 320C without major modification?
Unless you have a fully-equipped engineering workshop at your disposal - unlikely.
Whats wrong with the 3066?
The 3066 engine parts are a problem to find in Malawi.
I see. A cummins 6bt might be a better alternative. Still would take alot of modification but it would fit better size wise.