My buddy is in the process of building a 383 for a customer, I told him to make sure and check the situation with the head gasket protruding into the chamber, and sure enough it was doing that. He said might he be able to find a gasket that works, but he was planning to pay around $300 to fix the heads if that doesn't work out. He wanted to use the cheaper heads so there is enough room in the budget for a hydraulic roller cam (to combat the last years' flat tappet headaches), and custom pistons (to have good quench).
So basically what I was saying that it's possible you'll have some head gasket/chamber mismatch that you'll have to fix somehow. Include it in your costs and you'll be able to make a decision on your own. As to it not being a real problem according to the 440Source...I'd rather be safe than sorry.

Ran