Exactly. I put my 451 together with mildly massaged 516 heads (larger exhaust valves, hardened seats, bowl blend) because I had them and wanted to get the car on the road. Despite the poor match to the 272@.050 cam. Low end isn't much (not surprisingly) with a 2.66 four-speed and 3.91 gears. So far I'm just breaking it in, putting around, and tuning, so the presumed fall-off at the high end when it really starts breathing was an acceptable temporary trade to get it on the road.
Meanwhile, I also had Dwayne Porter do a Stage 1 job on some Speedmaster aluminum heads, which are now on the shelf waiting to go on once the heat/humidity breaks and allows working in the garage! 295 cfm @ .650 should wake it up
