New 383 motor in '32 Ford pickup in stock boxed frame. The motor mounts are located at the front of the motor by two (one on each side) bolts attached to the frame. Under hard acceleration the driver's side bolt stretches or breaks. Probably not the best way to mount a motor but I understand that the bolts wren't meant for 400+ power. I'm considering using aircraft grade bolts. I haven't tried Grade 8 bolts yet and that's my first step. I need bolts that minimize the " stretch aspect" . Any help or advice will be appreciated.