There, should be a heat shield on the drivers side . It attaches to the floorboard then bends up 90 degrees and goes in between the manifold and the doghouse/ engine cover.
They are often missing/removed for what ever reason.
Also the 440 wasnt availible in 1974 From the factory in the class C chassis or vans, so if you do indeed have a 440 in a 74 C chassis it was shoehorned in there because the factory made some changes to the engine cover and engine bay to fit the big blocks in 1976 or 77.
With it getting as hot as you say , there,s a chance it might ignite something.
