Hi all
1951 D47U. Runs great, performs as it should. A little rough starting cool. In warm weather, it's great. Cool starts, 20 degrees, it starts, but drops a cylinder or two for 2 minutes. Then smooths out, and ready to work. For the first one or two seconds, it hits on all four cylinders, then drops one or two, eventually to pick them back up. I used a non-contact thermometer, and cyl 4 is cool, till it finally picks up. Also, after an hour of work, my manilold temp read 156, 246, 245, 244. Number one seems to not be contributing. This has happened several days, over a year, same result. Any ideas?

Would you have loss of temp due to Fan pushing air past? if cool ambient temp this could make the difference to front port on manifold area