I believe you should really take your transmission final gear ratio into this cam equation. I found the OD of a 200R to be.67 which means a final gear ratio of 2.29 when your in OD cruising. You didn't give us the tire size or weight but what ever cam you choose consider advancing it 4 to 6 degrees to get the use of it at lower RPM. My son and I put in a "RV" grind in a 350 once, 258 duration and .460" lift. 350 Turbo trans. 3.55 rear. It was a dog. Advanced the cam 6 degrees and you couldn't catch it. Towed my 40 Chev on a tandum trailer like it wasn't there. Just something to think about..........Good Luck
