unsilences - dual snorkel aircleaner and straight v turned down exhaust

[XH29N0G]

I have been looking through the posts to try to understand some things that have been mentioned and also some aspects of the charger I have. 

Can someone school me on the use of dual snorkel aircleaners and turned down exhaust on non CA cars from 1970? 

I have an XH charger with a 383 magnum, bench seat, 3 speed on the floor, heavy duty suspension and AC (bought as a family car).  It had a dual snorkel aircleaner and turned down tips on the exhaust. 

I take it that most dual exhausts and HP engines had unsilenced aircleaners and straight tube tips - at least for 68 and 69.  Was there a change in 70 with the economy XH versions, or does this something a little strange.  The car was ordered in January 1970, built in March/April 1970 so it is not particularly late.  (Aside:  If anyone has an idea for a drop base modification for this, I would like to hear about it.)

Thanks for any information or any directions on where to look for an answer to my question.