I am getting int the process of installing a 351 w into my 72 fastback 4 sp car. I can't seem to find a pair of header that will clear the Z bar. I modified a pair of try-y headers for my 302. Is does'nt look like it is going to work with 351w. I would like full length headers.
Check out www.fordpowertrain.com They list one set, but call them and ask about what you want. These are not cheap headers, but in off the wall applications, they're many times the only choice. I bought a set for the 68 Merc I had till last year. Can't beat the fit and finish. They offer many sets for Ford applications you won't find anywhere else.
Ford never put a 351W in a 72. All the 351 were Clevelands. And the 71-73 engine compartment was different than the 67-70 so there is no guarantee that headers for those cars will work.
You might be SOL. FPA can help you if anybody can.