Yep, old trends are hard to break, and has driven up the price of the 207's over the years. That surprises me, as they have no performance advantage whatsoever over any other Chevy divorced choke carburetor made between 1969 and 1978. Change 4 airbleeds, idle tubes and a couple of bypass air holes and any other casting is dead even with a 207, and most can be had for $5 to about $25 at swap meets.
Several ways to go with the fuel inlet seat and float. The fuel delivery system must be adequate for the power level. I prefer to stay slightly smaller with the inlet seat, run a small float, and then a tad more fuel pressure. Contact us by phone or email and we can go over specifics and get you the correct parts, etc.....Cliff