Our winters can see 85 F here. Even back in Oklahoma it wouldn't be unusual to wear shorts on Thanksgiving or Christmas but the next day it's -14F windchill.
Wonder if the OP could rig up a dual snorkel air cleaner with 2 heat risers?
That was my idea. I've run my Duster when it's 10 F and it does OK since the cam doesn't have a ton of overlap but would definitely benefit from a dual-snorkel air cleaner with hot-air intake until it's fully warmed up (open-elem. My truck's 360 has a Performer intake with stock iron heads but the heat crossover is blocked, that thing runs exactly how the OP describes when it's below freezing outside and it still only has the stock 2-barrel cam. I do drive that pretty often in winter so I think that'll be the one that gets a hot-air intake first.