[Coley]

You've come to the right website for some good advice and insight on your truck.

First, the move to dual exhaust is an good, easy idea if you can do it economically....no harm, nice to have and helps with tuning the engine or finding a missing cylinder/spark, etc.

As for changing the stock ramhorns over to headers....I would say reconsider this.
It is very unlikely, if not completely unlikely, that you will notice any difference at all in power or performance with your engine.

The original ramhorns provided pretty good flow for these motors from the factory...the headers advantage only shows up on higher performance engines and higher rpms'....so this might be time, effort and cost with very little if any payback.
...apart from the underhood noise and leaks, lol.

More pics of the truck!!.....but based on the minor engine pics...it looks to be pretty original and pretty nice.

All good
Coley