302 heads to 273 - head bolt help

I would check the valve to cyl wall 1.88, 1.60 are .200 wider than the stock valves and depending on your lift they might hit the cyl wall. I know the 2.02, 1.60 will hit the top of the block because the valves are bigger than the bore.

Where are you getting 1.88, 1.6 valves???