I would like to streamline this GX35 for mounting it with as narrow a profile as possible. Ibraze and tig weld, so the possiblities are not limited.
I anticipate routing the exhaust and carburator toward the back (output shaft faces aft for this application). Prop vacuum/pressure is not an issue since this is not for flight but for a ground vehicle.

Do Ireally need a formula? Or will Ibe pretty much OK simply maintaining proper ID and fabbing an intake that wraps around the cylinder rearward while trying to keep the length as short as practical?