the 348 pontiac motor is a good truck motor,dads 56 gmc had one.better for 3/4 applications.gms truck motor plant burned down in mid 50s.so 348 pontiac,olds of that vintage,buick 401s and in big bolts a occasinal caddie motor was found in gm trucks.all would work better than a 283 if ya gonna pack weight or have lots of hills.just my .02
