Whats the difference between the truck and marine engines compared to the passenger car engines?
They share alot of the same parts like crank and rods but the heads and block are different between them. The truck and marine blocks have a cut out area in each cylinder that helps lowers the compression to 7.75:1 The notch in the block is not responsible for all the compression loss however. The truck and marine heads (333) have a combustion chamber and shorter pistons which are responsible for the largest amount of the compression loss. On a positive note, the notch in the block also allows more room around the exhaust valve thereby enhancing the air flow. Back to the top Q: Are they any easily visable ways to tell a truck 348 or 409 engine from a passenger car engine without removing the heads? A: For the 1965 #3857656 block, look on the lower front of block on each side of the timing cover. On the left side (right side when standing in front of engine) there are two 7/16″ coarse thread bolt holes which the power steering pump bolts to. These are drilled on all blocks both car and
