72 the k member for sb and bb is the same.
It sounds like you need to go through the motor. You want to make this trip!! You might be able to just hone the 318 and maybe polish the crank... see what you have.
Most the 72 318 cars have 2.73 in a 8.25 rear. That is already highway geared, ready for a road trip. Simple to check and see what you have.
Going to a bb isn't that big a deal to swap if it is something you want later...but first things first I would get the car road worthy
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