If you have a long pipe running for most of the transmission tunnel then it will drone.  Your silencer or a glass pack, placed in the middle of the long run, will quiet the drone.

 

A glass pack will flow better.

5 hours ago, Grubb240Z said:

Update: After visiting the local police department and having them tell me they can't sign off on exhaust - I'd need to go see the CHP, I did just that. CHP officer gave me a little bit of a hard time about my header, little filter on my breather, etc., but he recognized that my '72 is pre-smog and let it go at that. Then, he asked me to start 'er up. After listening to the idle for a couple of seconds, he asked me to rev it a few times. My silencer did the job and he said "Sounds like it should be fine". He signed off on all three of my issues (brake light, front plate, loud exhause) and I was on my way. Whew! 

I'll try to get around to posting a before/after silencer video soon.

Nice,  always fun to stick it to the man.