The M55 used components of the M46 and M47 Patton tanks., but the automotive aspects were reversed. The engine was mounted in the front and drove through a front-drive sprocket. The driver's cupola is visible on the front left of the turret, and his doors are visible on the side of the turret under the cupola. Directly behind the driver's doors is the outlet for the turret ventilating blower. The rear spade can be seen in the lowered position. Spare track blocks were stored on the turret front on either side of the howitzer. The mesh screen just in front of the turret is the left-side rear air exhaust duct; the left-side forward air exhaust duct is right above the drive sprocket, but was not covered by a screen. The three square plates on the hull front were transmission access ports; on early vehicles the center port was lower on the hull than the outer two. The round cylinder above the howitzer is the telescope cover support. (Picture courtesy Armor Foto.)