Independent auto safety design consultant Byron Bloch, calling the 1973 Pinto fuel system design defective, showed a jury today slides of the crashed Pinto in which three girls died in August 1978, and declared that the defects contributed to the rupture of the car's fuel tank and the subsequent fatal fire.

It was Bloch's second day on the stand. He is the first of three expert witnesses the state plans to call. Ford Motor Co. is being tried here on three counts of reckless homicide. This is first case in which a corporation has been brought up on criminal charges arising from its design of one of its products.

Block described one slide as showing how the Pinto's fuel tank attempted to "ramp over" the rear axle of the Pinto. But, he said, the tank's safe movement during the impact was hampered by the car's differential.

He also showed how the tank apparently was caught on the car's rear axle near the tank's welded seam during the crash and ripped open.

The jury viewed another slide that showed a large hole in the floor pan of the Pinto leading to the passenger compartment. Bloch attributed this to what he called another Pinto defect.

"It's important to maintain the integrity of the floor pan so it won't pop apart" on impact, Bloch said. He added that otherwise the car's body "can't resist the intruding vehicle" and if the fuel tank ruptures, "gas, flames and heat will penetrate much too quickly."