So I have my rig folding and have questions about my temps. Here's a line up.
 
ron@ubuntu:~$ sensors
coretemp-isa-0000
Adapter: ISA adapter
Core 0:      +71.0°C  (high = +80.0°C, crit = +98.0°C) 

coretemp-isa-0001
Adapter: ISA adapter
Core 1:      +78.0°C  (high = +80.0°C, crit = +98.0°C) 

coretemp-isa-0002
Adapter: ISA adapter
Core 2:      +75.0°C  (high = +80.0°C, crit = +98.0°C) 

coretemp-isa-0003
Adapter: ISA adapter
Core 3:      +74.0°C  (high = +80.0°C, crit = +98.0°C)
 
Typically, core 1 goes between 70 to 72, core 2 between 74 to 80, and core 3&4 between 74 to 78. I'm guessing that core 2 temp is higher because of TIM issues. My question is why do the core 2 temps swing so much? Any ideas? TIA

I've got an 8°C difference from 3 of my cores to Core #1 (my hot one) under load.  This seems to be extremely common on these processors.
 
Just a heads up:
Awfully high temps for 24/7 folding.  If you go over to OC.net, you'll find quite a few posts where 2600k (s) have degraded in the very short 3 months they have been out.  OC'd similar to your's 4.5-4.7 and voltages anywhere from 1.3 - 1.5V, and with constant temps in the mid to high 70's.  The first sign has been a necessity to raise voltages to hold the same OC stable that has been running for 2-3 months with no other changes. 

Thanks. This is good information to know.