I'm slowly putting back together my 72 Cuda after it's paint job, and i'm in the process of putting the wiring harness's back in and wiring up a sound system. The motor will not be going in for a while but I would like to test the electrical system (lights,audio etc)

To hookup the battery temporarily (which is in the trunk) Can't I just run the positive cable to the starter relay and negative to a good body ground ?

I just did the amp meter fix and bypassed that problem.

Am I missing anything or any suggestions !

don't see why not.

If there's no dangling/loose wires you're all set. What I have done is just take a 75 cent inline fuse holder put in a 20 A fuse & add a pair of small alligator clips on each end & hook it inline like at the batt positive or negative terminal. Much better than smelling smoke.