Why a Jack Plate?A jack plate will compensate for a long shaft engine!Product SpecificationsThis Jack Plate is designed for smaller motors to improve the performance of your boat. Two pairs of precision machined aluminum angles locate the motor with 6" setback from the transom. Slots in the angles allow 4" of vertical movement to position the motor in the correct location for maximum output. Stainless steel bolts hold the angles in place. This Jack Plate is rated for motors up to 150 hp and comes in an attractive polished aluminum finish. Fits all V-4 and V-6 standard bolt pattern engines. Some special drilling of holes may be required on engines manufactured before 1980, the pre-drilled bolt pattern is listed below. Made of high strength polished Aircraft Quality AluminumOffers 4 inches of adjustable Vertical movement6 inches of setbackWeighs 20 lbs150 Maximum Horsepower Jack Plates are the perfect solution for long shaft engines with a short shaft transom! The engine side holes of the Jack Plate are drilled 1.500 inches higher than the transom side. Combined with the 4 inches of adjustable vertical lift you can obtain 5.500 inches at a maximum height to raise your long shaft engine and make it workable on a short shaft transom boat! Here are the pre-drilled hole dimensions listed below in inches: Pre-drilled holes for 1/2'' stainless hardware12 7/8'' across the top two holes from center to center9 7/8'' across the bottom two holes from center to center8'' of vertical distance between the top holes and bottom mounting holesAttention:If your holes do not match this configuration, you can drill into the aluminum plate.