I think I can help you. I have a 400 & 450. They're virtually the same except the 450 has small dial & handle on the front. Let me look if I have any pics when I get off work. If not, I can grab some pics and/or dimensions this weekend when I can get to the pump.

I'm curious does yours still have the small reset handle that has an arrow on it with the word "Up"?

Ryan