300sdl head replacement #14, 17 or 22? need experienced feedback
 

After a 4 month long rebuild from a blown headgasket, I am back to square one. Same problem it appears, there is exhaust in the coolant so I am looking at tearing this thing back down again and starting over...rather discouraging for one new to Mercedes, but I will not give up..I really like the car. I do need some experienced feed back on the best choices once I get back down to the head. Although mine has the original 14 head, it was resurfaced within specs and everything measured out good...but there was a slight crack in the #5 valve that we did not think would cause an issue since it didn't involve the water jacket. At this point I am assuming this is where my problem is...will check and know for sure once I get it torn down again. But I want to replace the head. What will be best? To go back with a #14, a 17 or a 22? What all has to be modified if I go back with a 22? I need specifics since I am new at this. Also, where is a good place to find used heads, that is reliable? Thanks!

If you have the room and time, consider buying a car with a good engine and use the head. Sell some of the other parts to offset expenses.