273, or 318?

Like @rumblefish360. said @Professor Fate brought up a great point. The crankshaft pocket is smaller on the 67. Machine shop should be able to handle it though.

I would keep the 273 since it's numbers matching. I had a 273 Commando in my Barracuda and swapped in a 5.9.

I miss the 273 winding up and pulling hard starting around 4500. It was fun!! The 5.9 pulls hard from about 1500 rpm, lol. Just a different kind of fun!