1) there were late heads used in k jet cars that looked like this and did not
have ports for fuel injectors as the injectors were not in the heads. It could be one of these heads that has been ported and milled. There were similar looking replacement heads as well - both for carbs and injection.

2) It could also be an R sport head as these were made from similar looking castings.

3) For a reasonable compression ratio with a 92mm bore, you will have to get above
50 cc in comb chamber volume. What is the depth of the combustion chamber?

4) Stop trying to modify the combustion chambers!!!!!!!!!!!!!!!!!!!!!!!!!
This was obviously a race head, whether R sport from the factory or modified afterwords. It would really be a shame to ruin an R sport head or even a good race head just to use on the street, especially if the modifications don't work.
To get race type compression, and 33 cc would be around 13 - 1, we take .200 " or more off the head. There is no way that you can take enough out of the combustion chamber to compensate for that. Trying will likely remove essential elements of the combustoin chamber shape. Not sure what cam, etc., you are using, but typical race ports, or R sport type III or IV ports would be too big for reasonable use on the street.

John
V-performance.com