71 318 rods could be floated from the factory. 318 rods from a truck engine are lighter than the 360 rods. the car 318 rods are lighter than the 318 truck rods. i have used both in engines before. if memory servers me correct, the truck rods are about 50 grams lighter, and the car rods are about 100 grams lighter. i have a set of truck rods at the shop. i will weight them and post the weight. kenny