Which SB?

You can use the 273 forged crank in a 318, I have a '65 poly 318 forged crank in my 340. The '67 small chamber heads will raise your compression but after the expense adding hard seats for unleaded fuel it might be better to use the '80's #302 318 heads. They are the small chamber and swirl port type head. The adjustable valve train is not needed for a hydraulic cam unless the motor you are ging to use has had a bunch of milling done then you might want the adjustable stuff to get your lifter pre-load right. But more times than not the non-adjustable valve train is fine with a hydraulic cam.