I'd start with the exhaust. 3" should be the minimum. Get a straight through style muffler like Magnaflo, Hooker Areo Chamber, Borla XR1. Stay away from chambered ones like Flowmasters. I'd next bump the headers up to 1 3/4" primary units.
The converter is definitely holding you back. Get a 4500 stall 8" from a quality manufacturer. I drove my 4500 8" verter on the street for years, just be sure to have a large cooler for the trans. A-1 or Ultimate would be my 2 top picks.
Porting the heads would be where I'd start if you want to get into the engine. Edelbrock heads are on the small side for a 4" stroker engine. Next would be the antique MP cam. Those grinds are antiquated to say the least. Bullet, Comp, Lunati among others all grind nice Mopar cams.
I don't think you'd find enough of a gain going to 1.6 rockers to be worth the cost.
