Another suggestion is It is time for gas companies to switch to alcohol
enriched fuel (: winter is coming...
I am in NC...

My head temps on my 73 2L T4 engine increases about 25 degrees during winter
with the change in fuel.  It drove me crazy the first time it did it about 3
years ago (I add a cylinder head temp gauge.  BTW my heads run @225 but now
with the alcohol 250 ). Checked every thing (Timing, main jets, plugs, etc.)
I got gas in a county that does not add alcohol and the temps returned to
normal.

Robert