The "Throw Away 318"

Many teens ended up with forged cranks. 318-3 truck motor is a common forged teen. Poly is a drop in but your better off finding a 273 forged crank. When's the last time you saw a poly crank for sale?
Both the 318 and the smogger 360 had pitiful compression ratios, first thing they did to to reduce NOx along with EGR. Flat top a 360 or dome a 318 (KB399 piston) and they are back up again on power.