It all depends on the rest of your combo. If you have flat top pistons, for example, or a small dome piston, you would want a smaller chamber to get your comp.ratio up a bit, like maybe 9.5 or 10/1... The mid to late 60's heads were closed chamber, like the ones you have...they were between 96 or 97cc, and maybe 107cc. Then they developed the open chamber heads, which are supposed to run 'cleaner', and it's reported they flow better, but you will find lots of arguments on that matter
..Anyhow, those were 188cc or a little bigger. So, to build decent c/r with those, you would need a much larger dome type piston. So, it all depends on what you want. You cant run just any piston with closed chamber heads, because of the shape of the chamber. Flat tops are OK, and they make a variety of dome pistons for those heads as well. Keep em, as Cable said, they are very good heads.
Oh, and your Dad sounds like a very smart guy:thumbsup: