5.9L Magnum questions

Your plan sounds solid, but the cam and converter don’t play well together. With that cam you could use a stock converter. And if you use a 3000 stall you could use a bunch more cam. For your plan, I’d pick small cam and stockish converter. Regarding exhaust, I wouldn’t even do the swap if I had to use stock 273 manifolds on a 5.9, just leave the 273 in there. If you do the 5.9 find a header that fits it’s that simple. Doug’s and TTIs are your choices. Have fun