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

old 383 Dart would start on what seemed like one cylinder, then another would kick in and sooner or later it would be purring at fast idle. that's when I'd kick it down and take off. probably 3 minutes or so.
Sounds like one of the 8.2l 4 stroke Detroit diesels we had in the mlvw our m35 clones made by the company that makes skidoo and seadoos