I have the PC680MJ (Metal Jacket). It is approximately 7"W x 6 5/8" H x 3" thick. I also have the optional auto terminals which brings the total height to approx. 7 3/8". With this setup I can use the existing Hoss battery cables. You can configure this battery on its back or side if height is an issue with clearing the seat.
Standing up it's no lower than the stock car battery unit and maybe even higher with the terminals for the stock battery cables. I took the terminal adapters off and put flat terminals on so it ends up lower. Two things. First, you can lay it on it's side and second , if you leave it straight up you have 3-4" of usable storage space in your battery box which is what I've done. Cranks the motor over as well as the full sized battery with less than half the weight and size. Good move but unless you lay it flat you'll not realize any vertical clearance..Joe