I noticed you threw torque into the equation. I f you are looking for gobs of low end torque and won't be running 7000 RPM, in my opinion, your stock heads will do fine. Why do I say this? Once upon a time I built a 350 with high compression (actually too high), a Comp Cams 268H cam set with 4 degree advance, Edelbrock dual plane manifold, and headers. It provided me with the pleasure of neck snapping torque and hp with the standard run of mill, plain-jane heads. If I were building a high RPM engine for the strip, then I would definitely invest in heads that can breathe better than stock.
As far as boring goes, there is old adage: "there is no substitue for cubic inches."
Bottom line is that it depends how you are going to build the rest of the engine and how you will use it.
Just my two cents worth, Skidmark
I would be careful. There was a recent member post in which he received one light and one heavy casting from some outfit in CA. If the heads are heavy castings and the same # castings, it would be a decent price for $300/pr.
the amount of horse power you would gain from boring would be negligible. by making the cylinder walls thiner you are allowing more flex which creates more blow by. As for heads there are power gains to be had a lower rpm with the right heads but choose carefully.