EPON

I have a 89 silverado 2wd with 350 tbi. It had 410,000 miles on it and tranny. Have no idea what kind of cam or tbi is and really I have no idea how the top half of a 350 works. So long story short 13 years later I warped both heads and 3 cylinders. For 13 years I replaced EVRYTHING on truck except tranny, motor, intake, and tbi/cam. I bought another 350 with heads. No intake or tbi. Put it in started it up and ran amazing. The motor actually sat in a hay barn for 2 years. That's all I know about it right now (stupid me) anyway I drove it for 2 days no problems then one day it really ran crappy. Little bit of blue smoke. Temp kept bouncing from 180 to 230 so I checked oil and it was little low. 1/2 quart. Checked radiator. Needed half gallon. Filled it up go to start it (it's still around 140 degrees) and it wouldn't start. I know why from my experience and what I heard. It was out of time. I ignition timed it with a light and FINALLY found that sweet spot. Drove it for a week ran awesome!! Yesterday I left for work. Got on the Hwy and above 50mph temp guage went to 240 just a few min. I drove home with it bouncing from 210 to 140. Got below 50mph and it ran solid at 170. (Normal temp is 190) everyone I talk to says if it ran hot on Hwy goin 75 it is either the timing or tbi. I know how to time my truck even without a light. But it is really acting like it isn't timed right at all. I've went high on ignition timing and it actually ran decent but idled high and burned real rich fuel smell. Still no hot start. Anybody with any ideas,or diagnostics? I would like to get a new tbi but have no idea what to look for. I forgot to say the electronic choke has always been a little weird as I was told by a great mechanic but never looked into it.