Re: 69 with battery in trunk, one wire alternator, MSD, nothing else w
OP says the car 'starts & drives', so that indicates that the block is connected ok the battery neg terminal.
That's not true, it just means the block is finding a ground. That ground could be from a multiple of unwanted sources. He mentioned a ground to the frame and one directly to the msd.
Your just jealous because you can't hear the voices!
1967 Olds Cutlass 468 BBC/T400
1963 Plymouth Fury 440/Torqueflite
2007 Ford Mustang GT (momma's car)