well the 400-205 adapter can be had all day long for $250... thats GM cast iron... ORW makes a cast aluminum one, I forget what it costs but its around that same price... so unless it was some super trick billet peice, with a real real reasonable price tag, i dont see it selling that well... however the rare birds like 465/203, 4l80e/205, (and others) would be nice... they dont make this stuff anymore so even if you dont make a lot of money off it, just that youre putting these parts back into people hands is a great thing IMO.
mike