Trunk Mount Batt. Opinions needed

OK, great news ! 1st a shout out to 67Dart273.Thanks for all the help and info. Although I didn't yet get to perform the tests you posted for me I did copy it all so moving forward I know what to do , your Post#48 did the trick, it turns out I had multible issues. 1- I welded a terminal block on the front frame rail for my ground wire.2 found two weak links in the Positive wires. 3- Replaced starter due to intermittant solenoid issues. Went to every connection adding copper star washers .
Then I put a New Ford solenoid in and the car and it just clicked (Bad out of the box!) so I put back the old one and boy does the motor crank over now. To think I put up with this for five years! (yes I'm a dummy). I still haven't fired it up yet as I'm doing a few other things to it right now but can't wait to retime and probably recurve the dizzy. Thank everyone for you input .