Gone to an auction and had not looked here for a few hours. At serial number 13121 on 4630 tractors the rockshaft casting was changed and the left hand SCV supply was changed to an external supply line rather than internal passage. Since the 84/8630 articulated shared the same casting design they were all the same. I believe all large frame row crop and 4WD tractors after those models share the external supply line to the LEFT hand SCV. High pressure oil out of a properly located power beyond block (left hand side) will be the same GPM flow as at the entrance of that SCV. The return through SCV coupler, the plug in the side of the SCV, the return passage in the power beyond block, the rockshaft return and a ported filter cup all will return the oil (the large pipe on the left hand side under the cab seat valve) through the filter and in to the charge side of the system. Hope this helps. One additional comment, When I install a power beyond block I install a needle valve in the high pressure side outlet before any hose connections. When a loader is removed the valve can be closed to relieve all pressure going to a loader control valve and helps with leakage when not being used. Also handy if a hose/fitting should blow. The valve with o-ring threads can be sourced from a 750/1560/1590 drill used to lock-up for transport and also from the accumulator float system on a 66,77,8820 combine. Makes for a clean non leaking install.