Exhaust questions, Heat riser, paint

Going to reuse stock manifolds on my 273. Should I remove the heat riser, it was stuck shut, I was able to get it open, the bushing is turning with the shaft, have removed the valve, shaft and all and tapped the manifold and just put short bolts on a 318 manifold, but would like to keep the counterwieght or whatever it is, could a I just remove the flap and then just put a couple tack welds on the shaft (inside the manifold) to keep the shaft from working out? or would I want to?
For those who have used the Eastwood high heat paint, how long after painting do you have to cure it?
Are reproduction heat shields for the drivers side manifold available for the 273.
Thanks