273 cam general driver/MPG/lowend ?

Been thinking of replacing my HYD cam in my 273. I'm not going to do the mechanical cam thing.
I was looking a Summits SUM-K6900 it says 1200-5000 rpm
204/214 @ .050
.421/.444 lift
112 LSA
I don't want some loppy/ shakey/ bad vacuum cam. But would like good vacuum, smooth idle cam with abit more lowend and something that maybe improve MPG.
So what should I look at ?
Oh yeah, I've got an automatic/3.23/ flat top pistons/ 4 brl/ GM HEI conversion / 3000 lbs Dodge A100/ 273 +.030....not looking for race car power.