Do you let your old engine warm up or just get in and drive?

I let the 1968 440 engine warm up a few minutes to get the oil flowing.
I run it long enough to where it can idle without stalling, then drive it easy until it is up to temperature. I don't have a choke so it is all foot and feather until it runs steady.
These flat tappet cams need varying rpms for proper oiling. No flat tappet engine will like long idling periods unless it is a stock slant six or 318 with weak valve springs.