360 Magnum building on an existing bottom end

Anyone have any experience with Speedmaster PCE281.1773 bare heads, 62cc chambers, 179 intake runners, setup for 1.92 intake valves 1.625 exhaust valves, 3 angle valve seat. They are reasonably priced for a budget build $339 a piece. I couldn't find any flow #s for these particular heads, but I have found for similar heads with similar intake runners, and those heads flowed at 260cc @ .500 - .550 lift. They are magnum style heads and I can build them up as the budget allows, that is why I'm favoring them. I have also looked at Edelbrock performer rpm heads but they are $700+ bare and $1100 complete. Can't justify spending that much just on heads alone, and I know the old saying "speed cost". But for a 60's street style gasser how much speed do you really need. Yeah it's fun to go to the track and make a some passes to brag what your car will run, but I don't have the budget to be competitive and break things. Besides there is always someone with more money and faster than you. So if you have any opinions or options concerning these heads please give them, I'm always open to any ideas that will help me make beast choices.