For the fuel you're running, you've got way too much timing . . For the average SBC. 36° to 38° is about average on Gasoline with the Comp ratio you're using. But this is nothing more than a generality. There's all kinds of things guys do with jetting and timing, especially in those roundy round engines with two barrel carbs . .
Any tuning gauge is generally relative, and depending upon the kind and how it's been taken care of, it may or may not give accurate readings. If you have any doubts about the accuracy of the Timing Light (or any other tuning or diagnostic tool) check it against several others.
On the EGT, just check the heat of the header just below the flange or the head right at the flange with a IR handheld temp gauge. Use it across all eight to not only establish mean or average EGT, but it will also tell you which ones are the hottest (Leaner) and which ones are richer or not firing if you have a problem . .
Your exhaust temp is relative to both your measuring instrument and the type of head/cam you're running. That you'll have to figure out, but a place to start would be using your gauge on someone else's combo that's similar to yours and then look at your's in comparison.