Oh Man, Header install fail help!

[thirstybob]

I tried every Yoo Toob how-to I could find. Broke bolt off in head removing stock exhaust manifolds...broke 2 easy outs off trying to remove it. Welded a nut onto the broken bolt, breaks the weld before it will loosen the broken bolt.
Now the question is, are 3909802 heads any good and is $850 a fair price. He states that they've been "completely gone through, ready to bolt on".
1974 C20 454 TH400

I'm supposed to look at them tomorrow.
Any advise would be greatly appreciated.