Follow up questions:
I have a vent (don't know the proper name) that is broken and needs to be replaced. Any suggesting where to buy a good replacement?
2. There is a hole in the deck covered up in picture that appears to have been a vent too. I am not sure what was there originally....something for the head?
3. I have two weird holes by outboard. Not sure what type of modification this was from. I am thinking to fill it since it sits safely above the water line. I have a suspicion they were drilled as fuel lines. Very strange.
I'm thinking your boat is a little newer than 1973. 75 maybe. Does it have a liner?
You can get the Hull ID off the right rear transom or from your boat title and decipher it.
You can't always go by the name/model of the boat on the title because they are often misleading or flat out wrong.
I have a 1973 Venture 224 that morphed into the Venture 25 2 years later and into the MAC 25 over the next couple of years.
It was a time of change for the Mac clan.
Until you decide what the future holds I would just glue up the cracks in that dorade someone rudely dropped something heavy on and throw SS bolts washers and nyloks with butyl in the transom holes (countersink first).
None of those vents in the top of your boat are stock.