Finally, my first 360 and goals for it! I'll be asking a lot of questions.

OK, got it. Well....

Learning a degree wheel isn't hard but it does take a little time to get a understanding and a good working relationship with it. Every time I degree a cam In, which is not often anymore, it takes a little while. You can find the duration in degrees. Desk top dyno had a manual input for this and it would spit back durations for you.

The mechanical 273 gear will work in a 360 head. The cam (270S) is small enough that it will be very good in torque. I would not hesitate to use it. You already have it.

If new pistons are out of the picture, then the head milling mentioned would be an excellent alternative. Considering the size it f the cam and the iron heads, I would not bother with more than a 9.0-1 ratio.

IMO, I think your going to have a nice machine there when your done. It will have plenty of torque. Your going up a serious amount in cubes and a bunch of it in stroke. Which equals torque.