I think someone was selling an entire 72 350 pretty cheap. Perhaps AVC1966? Use the search function and you should find it. Good Luck
350 heads I bought a set freshly redone from a machine shop/parts house that had been in business for 30 + years when he closed. The heads have a 74 cast into the head. I was going to put them on my son's 70 350 but discovered that the 70 block is different and did not want to make the modifications for them to fit. I paid $250 for them. Hardened seats and all.
shipping would be a pain, but if my old 72 350 hasn't been junked yet, you can have mine. Car ran good till cam broke, don't think there is anything wrong with the heads. I did have to pilfer some spring retainers for my 455 tho. Shipping is all, but on heavy heads that's up to you.
heads I think that they are right for 72 up. I am not sure where the upper cut off is if there is one. Somebody may jump in and help. Send me yur zip code and I will check shipping costs. My guess would be about $50.