I know that these head conversations can get a little opinionated but I'm pretty clear on how I feel about the cut rate heads. Yeah they are poor china knock offs and yes, there are people who get bad castings and have geometry issues, no question. On the other side of the coin you can sometimes get these heads under $500 a set and at that price it's not even worth attempting to do anything on an old set of heads. I have been looking for a used set of aluminum heads for 2 years now. Cheapest price I've seen is $850 for some Edelbrock ones used. I can get the Edelbrock 351 heads new through my parts guys for just under $900 so not paying $850 for used heads.
I've got 3 sets of alternative heads. GT40Ps, E7Ts and a set of 69 351 stock heads. To do any machining on these heads of any kind will cost well over $400. Way I see it you can buy a cheap set of questionable knock offs for $500, fiddle around with them and get a decent flowing smallblock head rolling. The other way is to get a set of old 2V cleveland heads off a 351M or 400M after 76 (proper seats) and block off the old water passage and drill a new water passage and grab one of the new "Clevor" intakes. I am really wanting to try this setup out. Got to watch the clevor setup though as the valve angles on the cleveland are very different than the windsor and you will want to check and double check the clearancing.