Many peeps with a 454 or 460, maybe even the Dodge 440’s would beg to differ. The big blocks commonly had manifold or bolt issues. Its the bane of rvers I know, had a chevy class C that needed a set. What wasn’t cracked was rusted out or through.
From plowsite.com:
“I changed the plugs today on my 98 K3500 with the 454. I noticed that the passenger side exhaust manifold is cracked in three places on the flange between cylinders 2 & 4, 4 & 6, and 6 & 8. The driver's side manifold does not have these cracks.
I've heard that 454's have problems with cracking exhaust manifolds so I'm guessing these cracks are not normal. It doesn't sound like I have any exhaust leaks. Is this the area that these things are prone to crack at? Anyone know a good source for used exhaust manifolds for these engines? Thanks.”
From IRV2 forum: “My 1999 gas Trek had both exhaust manifolds crack. The choice was to replace with new cast manifolds or headers. I researched Banks and was told they only had materials for 4 more 454 header sets then the product would be discontinued. Jegs & Summit still had Banks headers in their inventory, so I bought a set of the "Long Tube" headers. Cost was $1400 and installation was $1600. This included drilling out 4 broken studs, cutting & tapping the length on some remaining studs that wouldn't come out so they fit the header flange, 2 new Oxygen sensors, and cutting off a large unused frame bracket…”
From the 460 forum:
“My left side exhaust manifold (stock cast iron) got a crack down the center of it this morning.
So I guess I'll be buying those fordpowertrain.com headers a little sooner than I had planned.”
Old threads but hey, it happened all the time. A lot of owners went back with long tube headers. If you buy a gas rv, even the V10’s will crack. The Ford Truck Enthusiasts Forum has several threads on it.
And here I thought the “hemi tick” was my main concern…