Help identifying pistons and cylinder heads

Did you measure the valve sizes yourself?
Are the intake port openings the 360 or 318 size?(in the pic, the exhaust port openings appear to be 318 sized to me)

Pretty much any new iron head you can buy now will be a magnum based head.

It’s not that big of a job to recut 1.78/1.50 seats for 1.88/1.60 valves.
(For me, I would only consider this if the heads have 360 sized intake ports. If they’re 318 sized ports, I’d look for some castings with 360 sized ports)
But depending on the overall condition of the heads, it’s possible to end up with a bigger bill reconditioning your(or other) old heads than many people think.
That will likely come down to what machine shop labor costs in your area are.