The ground circut should be beefed up on older cars. This may / may not
GM cars have thickly painted alternator brackets, the ground fastens
with a sheet metal type screw. Unfasten ground, and move it to block
itself, clean connection points. For the ultimate, use a stainless steel
bolt. To be even safer, run an old battery cable from frame to block. This
will probably brighten your taillights, which dim on older cars.