forged crank

1973 Will Be A Cast Crank. I Not Sure Of What Years Used A Steel Crank, Maybe 1969 & Earlier. I Know That I Used 318-3 Truck Steel Cranks From Ed Hamburger In The Early 80's. A Cast Crank Will Have A Thin Cast Parting Line On The Rod Throws & A Wide Ground Down Parting Line On The Rod Throws.