Those longhoods were built to take many different engines, I have seen 855 Cummins engines in them, also a 3406A Cat... Not sure if that was a factory offering... but the engine fell into the vintage of the truck. They were also available with the 12V71 Detroit. Myself I prefer the single headlights like the shorthoods used but the longhood used the smaller grill structure similar to the butterfly hood gassers with the low mount cab. I have seen one longhood with single headlights a long time ago.