Look on the block identifier pad. If there's an "E" there it is a cast crank.

I highly doubt that any 71 half-ton had a forged crank. I've got one in my back yard and it has the "E" on the ID pad. Of course, it's a Mopar, never say never!

The real question is why you think you need a forged crank. 318/340 cranks are not prone to breakage at power numbers the block can handle. Forged cranks don't make more power. Dirt track sbc 350 drivers use cast cranks as a matter of course.

What's happening to the rest of the truck? Out here they are becoming more popular smoothed and dropped.

R.