Put the VACUUM MODULATOR in now, after lubing & checking free motion of the MODULATOR VALVE in the case. I like to reuse the original VACUUM MODULATOR (after testing), because it's the only one with altitude compensation. However, it's about the only one that's NOT adjustable, and you may need that feature later for fine tuning. The REAR SERVO ASSEMBLY goes in just before the valve body. The factory manual discusses testing for the right length BAND APPLY PIN. I have NEVER seen any pin except the standard length, so just put it back & don't worry about it. When bolting the cover to the case, make sure the threaded part of the bolts is 5/8" long. Some units may have shorter bolts, which risk stripping if you aren't as precise as the factory. A SWP valve body was used with the early cartrige oil filter & "heelprint" pan. I use the later filters, with the 68 or later valve body, special filter retainer bolt, pickup tube, and deeper pan. You may modify a pre 68 valve body by drilling & tapping 5/16" NC for the filter support bolt. Note that the later valve bodies have a flat spot machined for this, but I find this isn't required. Drill a smaller hole (not quite through) for the tap, and drill 21/64" for only about 1/16" deep, so that the unthreaded part of the bolt can fully seat. Use a drill press to get the hole perfectly square. The BIG concern here, is NOT to get any metal shavings into the valve body valves. If the whole assembly is dis-assembled & cleaned, fine. I have carefully taped up the whole thing so that only the hole location is exposed, which is WHY I don't want to drill through to the sensitive other side.