This specially designed aluminum mount for 3W 157cc motorsused on models that have the right thrust built in and weighs less than 2 oz. These will save you a lot of time and effort. Machined from 6061-T6 with a 5/8 rise at the highest point . Just draw your horizontal and vertical center lines, then line up the cross hairs on the mount. There even is 4)- #4 holes so you can mount it to your firewall and use it as a drill fixture. 4)-1/4",4)-1/8" & 4)-1/16" boss extensions included.