What weight oil

Redline. 5w30 or 5w40 depending on your oil pressure at maximum operating temperature.
Otherwise for a cheap solid option, check out rotella 10w30. Alternately if you must have really thick oil (which is usually totally unnecessary for street engines), Rotella 15w40.
I am running rotella 10w30 with hughes oil additive in all old type engines. But our winters are minimum 25 degrees and I would never start my old mopars in that cold of temp anyway. If it was 20 degrees or below, doing cold starts, I would probably look at running 0w30 or 0w40.