need help

The metallic popping sound could be the exhaust flapper banging around in the manifold, my first slant did that when idling in gear ( 650 -750 RPM range ) when cold. Just about drove me crazy for a long time until I saw the weight bouncing back and forth with the hood up one day while scratching my head trying to find it...
...oh, and a good test of the hot start issue is to drive the snot out of it for about 10-15 min, park in your driveway, open the hood immediately, wait for 10-15 min ( the usual heat soak time ) then see if it starts normally. With the hood up it should bleed off the heat that normally would boil the fuel. I did the fuel line / carb spacer mod with great success here in FL.