If the bowl screws weren’t 12-24, then they had been swapped already(from the body being stripped previously?)
I was thinking about the carb issue you’re having and thought of something that was discussed in another thread.
The base gaskets aren’t necessarily exactly the same for a Demon and a Holley.
This thread, posts 555 thru 566 explain it with pics.
Might be an issue on your carb, might not. Holley/Demon Carb stumble
