Next you need to center a Great planes .40 MM over the hole in the remaining firewall. The Jeti motor is then strapped inplace with a hose clamp. The back of the motor is one inch from the MM base with the adjustable mount closed all the way. The motor can be slid fore and aft to get the alighment you prefer. This will center the motor with the cowl when you attach it. Consult the airplane's manuel for cowl attachment.