I to like to overpower my models a little bit. The thing you are forgeting is the age of these kits. A .40 size engine from 1970 made as much power as a .25-.30 size modern engine. Thats the kind of power those kits were designed for. It's not so much the displacement differance thats hurting you it's the combo of modern power plus more displacement. Can you give us some specs on that 325? later daveo