Hi William,
This ProMaster Scopema swivel raises the seat height by approx. 1.25". We also offer a lowered seat base that will maintain the factory seat height when paired with a swivel. You can find the lowered base here:
https://www.eurocampers.com/2014--2024-Ram-ProMaster-Lowered-Seat-Base--In-Stock_p_1837.html