Summit Headers

Need some advice on a set of headers from Summit, the guy says they will fit a early A. There book says 67 for sure, I have included the link take a look please. Also what is the difference between 4-5-6 273 and the 7-8-9 273 as far as the drivers side set up with the steering box torsion bar and all the other stuff, I would think its the same and would fit. Here is the summit part number, SUM-G9040

http://cgi.ebay.com/ebaymotors/ws/e...107007594&viewitem=&sspagename=STRK:MEWAX:VRI