can you look at a picture of my Crank?

[jocko]

it looks like a cast parting line on the counterweight (i.e. thinner than a forged one) - but like Livrat said, very hard to tell in this pic. If you were to take a pic from the front - showing the part Livrat highlighted, you might get a more definitive answer. Also, pretty sure factory cranks for trucks are cast - is this yoru stock motor out of the 69? Forged was usually high-end stuff for the high-end musclecars, etc.

[70blackfish]

i bought this motor not knowing much about it. from a friend of a friend. deal...
he didnt know it was a 4 bolt main and also didnt know about the little rust spot. im not if i should just run it this way....