I followed all the steps to build the 20-20 town tune. I also put the timing below 20mm3 to sock so it dled right. I ran it today with cooler weather than we have been having and it was hot. When I get on the freeway and start going 70mph my truck instantly heats up to almost 210* when it normally always runs right around 185*. The instant I get off the freeway I can watch the ect gauge drop back to 185*. Could this be from the extra boost or what? Doesn't seem to get very good milage either. Also the egt don't seem to be running much cooler than stock. Any ideas?

The 20/20 tune is a good starter tune, but is far from a refined tune. Yes it will run hotter from the added timing and boost if you did those parts. It is a good tune to help you see what changes can be made to increase the output, but there is ALOT more that can be done to make it refined. You've done the first step, now it's time to take it to the next level and start tweaking it to how you want it to run. Also check the library and see what is in there for milage tunes.

What would you recommend to start messing with to get it to run a tad cooler get some more milage out of it? I am going to be towing a bass boat this weekend and will probably just use a stock tune if I don't get this figured out.

Go into the FAQ and download the timing calculator. Also try and keep your changes all in the lower right of the fuel tables and make them progressively come in rather than all of the sudden. Small changes are your friend here as well. You just have to get a feel for it as every truck is different.

From what I have learned a higher boost will lower your mpg because of the added cylinder pressure.
What ingition timing are you running at cruising speed?