27000 miles on f350 gas truck not diesel both cats were replaced because they were clogged. 32000 miles now and getting replace again because they are clogged again?? also manifold gets cherry red

It is the converter maker that is the problem...I work for chrysler and we go through the same thing.
It seems that it is mostly our vans ...I just changed another one today..Your truck should be ok but if it was clogged enough to make the ex. manifold get red that is real bad !! ...
I have seen the converter itself get red but never a manifold..in 25 yrs. If you have warranty be sure they inspect the manifold for cracks....Once it has been that hot it is weakened...If it gets very,very hot then very,very cold it will crack easily ! I live at myrtle beach so if you are in a place like that you will be safe....So I believe it is the converters because I change a lot of new ones.....
Hope this helps....................................Metalpoet...........

If you are in the USA, take it to the dealer. Suppose to run for 50,000 miles with no problems. This is a EPA reg.