From the orifice, oil travels to the left side of the transmission via a drilled passage in the top of the case.  There is an o-ring in the case joint to prevent the pressurized oil from leaking out.  The area circled in red is where the drilled passage resides.  The plugs circled in green and yellow seal off the ends of intersecting vertical passages that carry oil to the transmission bearings on the left side.  I don’t think that oil is intended to lubricate the trans bearings because they are sealed.  The oil running through this circuit is intended for the internal idler bearings in some of the transmission gears, and for the clutch bushing.

Oil enters the end of the input shaft and provides lubrication for the idler bearings in 4th & 5th gears.  The oil continues to flow through the shaft to the right side of the engine where it lubricates the clutch bushing.

Both sides of the input shaft are open.  Oil enters the left side of the shaft so the left side must remain open.  The right side of the input shaft must be sealed off to prevent the oil from just running out of the shaft.

Oil enters the output shaft through this small hole.  Never obstruct this hole by installing the pulley spacer backwards.  The notches in the pulley spacer must touch the inner race of the output shaft bearing, not the pulley.  The oil in the output shaft lubricates the idler bearings in 2nd, 3rd & 4th gears.

I was curious how much pressure to expect downstream of the transmission supply orifice, so I made a test connection to replace the pulley and spacer.

So, under low-speed cold conditions the trans pressure is about 5 psi.  Looks like it might be safe to assume that with a .071” orifice the trans pressure should be about 38% of head pressure.

I know, this is a crude gage installation, but what the heck, it’s temporary.  At least the test fitting was pretty.

I decided to use the high-speed pump drive because I could restore the system to stock configuration without completely disassembling the engine.  Let’s face it, I was exploring virgin territory.  The increased flow would allow an additional oil circuit with a dedicated spray for top gear (in my case 4th).
 
To utilize the high-speed pump, I would need a way to control flow to the various circuits and bleed off excess pressure.  That could be accomplished with jets placed in strategic locations.

The primary objective was to provide lots of cool oil to top gear, and the secondary objective was to increase pressure to the cylinder head.  If I could maintain at least 7 psi at the head, I knew that the original oil circuits would still be receiving the as-designed volume of oil at the as-designed pressure.   But if I could increase pressure at the cylinder head, every component in the engine would benefit from additional oil.   Any pressure over 7 psi would be gravy.

To achieve the “cool oil” objective, I would use an oil cooler.  I don’t think the Savage needs an oil cooler.  My oil temperature has always been a bit cooler than desired (about 200°F here in Hawaii).  But I wanted that gear running cool.  So, if I restricted the flow of oil through the cooler, maybe I could achieve the goal of cooling the gear without reducing sump temp too much.  Running the pump at higher speed was gonna heat up the oil a bit too.  Maybe one would offset the other.

The DR cam would get the requisite oil holes in the cam lobes.

This is a diagram of the modified system.  The 4th oil circuit (in red) runs from the main oil passage, through a jet to control flow, through the oil cooler, and through a spray tube directly into the gear mesh.  A bleed jet is installed in the oil filter housing to dump excess oil if necessary.

This oil system upgrade wouldn’t prove much unless I installed it on an engine with some yank, so I simply moved the entire top end and 4-speed trans off my Big Bore 4-Speed project over to the oil system test mule.  Up to this point, the Big Bore 4-speed had proved that it was up to the job.  It had overwhelmed the clutch, destroyed a main bearing, and seized a piston.  This thing makes great power.  It will be a good test for the modified lube oil system.

A special fitting taps off the main oil passage where the plug used to go.  The fitting has a provision for a thermo bulb.  It has an integral 3/8” hose barb that is drilled & tapped to accept a standard Mikuni main jet.  The jet will allow me to control how much oil goes through the 4th circuit.  I use the jet as a primary control for oil pressure, and to prevent over cooling the oil.  I want to try and maintain oil temperature about 200°F.  If the cooler gets good and hot, I know that there is significant flow through the cooler (more than enough to lubricate and cool the gears).