How does the trim ring fasten to the hood?
The trim ring is a bond on affair. After the hood hole is cut and your shaker is secured in it’s proper position, apply an adhesive or sealer to the inside bottom of the trim ring. Use a narrow bead like 1/4″ . Put the trim ring in place, adjust as necessary and apply tape to keep it from moving. I do not recommend using quick dry adhesives as they greatly reduce your working time. You need to take your time and be sure you’re satisfied with the fit because it will soon be permanent. Also be sure you primed & painted all bare metal to prevent corrosion.