Building a surprise 67 Cuda for my Pops

AJ/FormS said
The 273 will be very peppy with 3.91s, and they are perfect to hit 60 mph @about 4400rpm in second gear. Very peppy. And yes it will probably need a SG.
'Course, 65=3300ish cruising

gonna look into those 3.91's but forgive me for asking, an SG is a Sure Grip correct?