Just because the cam fits the engine doesnt mean it will perform right. If you run to much duration you'll end up with a motor that makes no torque and wants to rev to 7500 rpms. That fine if your seting the rest of the car to use it and if your building a race car.
273 heads wont flow enough air to use that cam, with your small bore and stroke you'll need 4.10 gears or lower. Its also going to want at least 10:1 compression. Even then I wouldnt run that cam in a 273.
If the car is a stock 273 with a small 4bbl, a 4 speed and gearing around 3.23s I would run something small like a CompCams XE262 or the Mopars 340 replacement. Either of these cams although small are still much bigger then the stock 273 2bbl cam.
If you rally want to run the 484 in your 273 by all means go ahead but you asked for opinions and mine opinion is that is the wrong cam for 99% of the 273s out there. Asl member Bill Paynter how is 273 runs with the 508 cam in it. He will tell you its a pig.