Truck compared to Car SBM

many truck LA motors used rotators under the exhaust valves, you can tell by the shorter springs and thicker retainers. I think some 318-3 truck motors used forged cranks past 68 and my have used sodium exhaust valves.

I remember reading the 70 truck motors had forged cranks. I had a 72 B100 Van with a 318/3speed manual/8 3/4" with a forged crank.