Truck engines had cast iron crank pulleys (all truck engines used a short water pump), passenger cars had stamped steel pulleys. Chevy went to the long water pump in 1969.
You really don't want a cast iron pulley because it adds weight to the rotating mass (which is why you pay to have high performance cranks gun drilled and the counter weights shaved to lighten them). The width of the V is also different as the belts were heavier to last a lot longer in constant use. A standard belt will fit in the groove (at the bottom of the V) but won't last long as they will begin to slip very quickly in use (been there, done that).
Corvette kept a short water pump up through 1974, which was the last year a BBC appeared in a car of any kind ('vettes have always been segregated from passenger cars, which is why I didn't mention them earlier). After that pick-ups and vans were your source of big block engines; as medium duty trucks and buses migrated over to diesel engines in the eighties.
To complete the L72 engine package, below are the other unique parts for this engine (Some parts like the 3872444 Bell Housing are not shown because they were shared with the L35 396 and the L36 427/390HP engines):
The crank pulley was cast along with the WP pulley..
Dave,The last big block in a Corvette was indeed a 454 in 1974 BUT the last Chevy passenger car with a BBC was the 1976 Chevy Caprice/Impala 454 and the last A-body's with 454 was 1975.In 75 you could get a BB Chevelle/Malibu,El Camino or a Monte Carlo all with the 454.
And Doug Marion of PHR and SuperChevy magazine fame (among other things) did a "Last 454" Malibu/Chevelle feature article that lasted for about 12 or more issues.
California emissions regs squashed the BBC 454 much earlier though.