Autocross Classification Question, Again?

Can I put a 914 2.0L (built from various years 1.8L and 2.0L 914 parts) in my 1972 914 and call it a complete engine upgrade (even thou 1972 never did not come with the 2.0L option) or do I have to count the points individually for the heads, displacement increase, etc?
Or
Can I put a 2.0L in my 1972 and run in CS or CP (and once again, even thou 1972 never did not come with the 2.0L option)?
And
Can you build a 2.0L from 1.8L and 2.0L parts and classify it as a stock 2.0L?
So is the initial clarification based on the type of motor or is it the year of car and the options based on what was available?
Or
Can I put a 2.0L in my 1972 and run in CS or CP (and once again, even thou 1972 never did not come with the 2.0L option)?
And
Can you build a 2.0L from 1.8L and 2.0L parts and classify it as a stock 2.0L?
So is the initial clarification based on the type of motor or is it the year of car and the options based on what was available?