273 cam general driver/MPG/lowend ?

That will be a good idling well manored good mileage cam. The 112 spec will have a nice idle. Not a muscle car kind but not super duper smooth like a stock 114 cam.
I ran a Crane cam with a 112. 216/228 @ .050 - .455-.480-112
Do a search on you tune for 74 duster exhaust and view my beige duster starting up on a cold day. It chops a little bit when cold and smooths out nice when warm.
You can search via my screen name as well, rumblefish360.