We extend to you a cordial "WELCOME ABOARD !" Come on in, make yourself at home, we are a friendly group of enthusiasts, and we also appreciate the classic Chris Craft Roamer, Corsair, and Lancer boats too , as they are all on the same family tree and share much in common ! Just start by posting a note introducing yourself to the group, that's all it takes here (we don't ask for or retain any personal information here, because our intention is to just "have fun and share information".
Respectfully, I think you are on a bit of a tangent...........the function of the t-stat is of no concern, nor are the holes we normally find already drilled in the t-stat valve assembly on many manufactured parts, but not all. The t-stat will work just fine either location.
The issue is the fact that by moving the thermostat block to the opposite side of the motor (along with the other castings and passages), we have in essence, created a place in the motor that will capture are and won't be vented.
In other words, by making this conversion the t-stat is nicely submerged but the air pocket is at the high end of the mntor where the t-stat used to be on the stock Q installation where it (and all the other associated passages and ports) could deal with an air pocket better. There will be air pockets in the motor from time to time, we just don't want to create a dry situation where there is one at the cylinder inside the block or in the head where all the heat is generated, thus the need for a small vent line. If you look over a Q motor now, even with the stock setting they decided they needed a steam vent line, and it may have been an afterthought, who knows, but in any case there is a small copper line leading to each exhaust log to vent out steam and air before it becomes steam.
Now that we are proposing moving the t-stat to the lower part of the motor we must deal with air pocket issues in a different manner to be sure we con't create a hot spot that causes someone grief later on by making this conversion.