Assuming a piston with 1.560" compression height and a virgin, uncut block, the piston will be down in the bore by about 0.025" when the piston is at TDC. If we figure 727cc's in the cylinder, an actual 66cc's in the chamber of a "64" cc head, (assuming the head has never been decked since new), 8cc's in the head gasket (0.040" compressed), 5cc's in the piston deck height and 5cc's in the piston crown, we might possible have a 9.65:1 static compression ratio. If that's the case, the cam would just barely slide by and work. What I'd be worried about though, is the lack of squish with the piston down in the bore at TDC. I suspect the motor would run o.k. on premium pump fuel though.
Keep in mind that the heads you are considering will be behind in the technology race by several decades, so they probably won't flow as good as the worst heads available in the aftermarket today. That, and the fact that you may have to spend more money on them than you think at this point. You will want to have them magnafluxed for cracks before you begin any work on them. And remember, we only have unleaded fuel today, so they will have to be machined for hard seats. Then the guides may be a little sloppy, so you'll need to replace them. The valve stems may be worn past spec, so they will have to be replaced. Then, you will want to mill the stud pads and tap for screw-in studs and guide plates. And on and on and on. You can see where I'm going with this. Pretty soon you've got over 800 bucks tied up in a set of junk technology heads and you could have had a set with today's technology for the same money.
I might be thinking getting a set of heads with 68 or 72 cc chambers. That would work out better with the pistons and cam you have now. Finish off the combination with a RPM or Stealth intake manifold and 1 5/8" long tube headers.
Here's a set of 70cc Edelbrock E-Street aluminum heads ready to bolt on for 900 bucks. The 185cc intake runners would be just about right for a 355 small block.