My Nissan 6 hp long shaft motor also has a clearance of about 1/23 inch. I use a Garhauer lifting davit to lift it into place. The Davis OB lifting strap that I use to lift the motor has a somewhat round cover that joins the two sections of the webbed straps. With that approximately 1 inch round addition added to the motor height, the lazarette barely closes and latches with some pressure, but then again, I don't normally latch the locker when under sail. Incidentally it was a great 10 to 12 knot sail out over the Submarine Canyon on Monterey Bay yesterday.