You might consider the cheap FE block hugger headers on eBay, especially if you will have the heads off for a valve job.  They fit fine on my '64 with C4AE-G heads (low riser, 8 bolts of course), clutch and power steering.  The reason I mention them is that with the heads off it was pretty painless to drop them in place, put the heads on and then bolt them up.  Of course with any headers some of the bolts are a pain to reach but it didn't take me that long, and I would think they have to be better than log manifolds.  Of course the '64 is quite a bit different than the '65 and later so no guarantees on fit to the frame, let alone the port and bolt considerations - just throwing it out there.

Pat