273 or 318 ?
A family friend has a '66 Coronet 440 2 door with a 273 and a 727 with an 8-3/4 with 2.76 or 3.23 rear gears. If it belonged to me, I'd have a 318 in it almost immediately. Not that I wouldn't prefer a 360. Or 340. Or a Big Block. A 318 would be a matter of convenience and affordability. I could get one together from my available resources quicker than anything else for the least work and money possible. The difference in performance and driveability would be worth every bit of the trouble to make it happen. But I would most certainly upgrade to later single pot disk brakes and split master cylinder before doing that. And I'd probably put a manual steering box in while I was at it, too. My take on driving it was the power steering felt like the tires weren't even on the ground, and the factory manual drum brake setup would barely be adequate for a slant six. Almost a two feet on the brake experience.