My guess would be the to te frame somewhere, I'm sure someone who has taken and put in a motor would chime in, I've notice that cars a have quite a few grounds. For safetly would be my guess.
From one of the studs of the motor mount to the frame rail. Look for the bolts with two ends. One end holds the motor mount. The other end is used for the ground strap.
From one of the studs of the motor mount to the frame rail. Look for the bolts with two ends. One end holds the motor mount. The other end is used for the ground strap.