93 4.0 need question answered

[tim93ranger4.0]

my exhaust just runs through the cat no muffler cause it rusted off.....is this bad for my truck messing with back pressure or anything? ive heard it could hurt the valves

 

[trail B2]

The problem that hurts the valves that i've heard of is cold air going up a very short pipe and cracking a exhaust valve by cooling it to fast.Not going to happen with a cat on there.Don't fall asleep with the motor idling though if it stops underneath.Carbon monoxide would worry me a lot more.

 

[alwaysFlOoReD]

^^^ I agree